• Users Online: 152
  • Print this page
  • Email this page


 
 
Table of Contents
ORIGINAL ARTICLE
Year : 2021  |  Volume : 4  |  Issue : 2  |  Page : 58-64

Can the pregnancy outcome be improved by incrementing progesterone supplementation on the day of embryo transfer in women undergoing fresh and frozen embryo transfer cycles?


1 Department of Reproductive Medicine, Milann Fertility Centre, Chandigarh, India
2 Department of Reproductive Medicine, Mother and Child Hospital, New Delhi, India; Department of Reproductive Medicine, Ferticity Fertility Clinics, New Delhi, India

Date of Submission09-Sep-2021
Date of Acceptance12-Jun-2022
Date of Web Publication30-Dec-2022

Correspondence Address:
Dr. Jasneet Kaur
Department of Reproductive Medicine, Mother and Child Hospital, D-59 Defence Colony, New Delhi 110024
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/tofj.tofj_6_21

Rights and Permissions
  Abstract 

Context: Luteal phase defect has been identified in all assisted reproductive technology cycles, necessitating optimal progesterone levels during the window of implantation (WOI) to improve reproductive outcomes. Aims: The aim of this study was to determine if incrementing progesterone supplementation based on the levels of serum progesterone(P) measured on the day of embryo transfer (ET) has an impact on the pregnancy outcome in fresh and frozen ET cycles. Settings and Design: A total of 220 women undergoing fresh and frozen ET were prospectively enrolled and received standard luteal phase support, an increment in P supplementation made if serum P levels were less than 15 ng/mL. Materials and Methods: Serum progesterone levels were assessed for all the patients on the day of ET. Patients undergoing fresh and frozen ETs were divided into two groups based on serum progesterone levels on the day of ET. If serum progesterone levels were found to be less than 15 ng/mL on the day of ET, the dose of progesterone supplementation was incremented. A correlation between the groups with serum progesterone less than and more than 15 ng/mL on the day of ET with the pregnancy outcome was then made. Results: No statistically significant difference was observed in the clinical pregnancy rate and biochemical pregnancies in the groups with serum progesterone levels less than or more than 15 ng/mL on the day of ET when an increment in the progesterone supplementation was performed (both fresh, P = 0.35 and frozen cycles, P = 0.056). Statistical Analysis Used: Chi-square test was used for qualitative analysis, and the Student’s t test was used for comparison of means. Conclusions: Measuring serum progesterone levels on the day of ET and incrementing P supplementation if serum levels of progesterone are less than 15 ng/mL to obtain optimal progesterone levels during the WOI in both fresh and frozen ET cycles might help in improving our pregnancy outcomes.

Keywords: Fresh embryo transfer, frozen embryo transfer, in vitro fertilization, luteal phase support, progesterone


How to cite this article:
Kaur J, Mahajan N. Can the pregnancy outcome be improved by incrementing progesterone supplementation on the day of embryo transfer in women undergoing fresh and frozen embryo transfer cycles?. Onco Fertil J 2021;4:58-64

How to cite this URL:
Kaur J, Mahajan N. Can the pregnancy outcome be improved by incrementing progesterone supplementation on the day of embryo transfer in women undergoing fresh and frozen embryo transfer cycles?. Onco Fertil J [serial online] 2021 [cited 2023 Feb 4];4:58-64. Available from: https://www.tofjonline.org/text.asp?2021/4/2/58/366157




  Introduction Top


Luteal phase support (LPS) has been shown to be an integral part of ovarian stimulation protocols in vitro fertilisation (IVF) cycles and there is a consensus on the need for progesterone supplementation in the luteal phase of all stimulated IVF cycles.[1] The etiology of luteal phase defect (LPD) is varied and highly debated.[2] However, the importance of supplementation with progesterone to optimize the peri-implantation milieu cannot be overemphasized.

Various theories have been postulated for LPD in IVF cycles. LPD could be due to removal of granulosa cells during oocyte retrieval, prolonged pituitary suppression due to agonist administration in the GnRH agonist cycles or due to supraphysiological levels of steroids, which directly inhibit the LH release via negative feedback actions at the hypothalamic-pituitary axis level (GnSAF).[3]

Progesterone is important as it helps in the secretory transformation of the endometrium by modulating the expression of giant mitochondria, subnuclear glycogen deposits, pinopodes, and nucleolar channel systems (NCSs), which facilitates the process of implantation.[4] Progesterone also enables implantation by promoting the immune system to produce non-inflammatory T-helper-2 cytokines. In the presence of sufficient progesterone, CD56 cells synthesize progesterone induced blocking factor (PIBF) which is a mediator having substantial anti-abortive activities.[5] A study done by Simoncini et al.[6] states that progesterone increases nitric oxide production bringing about an improvement of blood flow and oxygen to the endometrium. Progesterone also reduces the contractility of the myometrium at the time of implantation, which is believed to promote implantation.

The importance of progesterone during the process of implantation and early pregnancy cannot be over emphasized and it seems plausible that LPD might be a cause of failing implantation and early pregnancy loss.[7],[8]

However, it is unclear if there is a cutoff level of progesterone in the luteal phase that may influence the outcome of IVF-ET cycles and whether increasing plasma progesterone at this stage can be considered as a rational approach to improve rates of implantation.

We conducted a prospective cohort study earlier at our center on 147 women undergoing fresh and frozen embryo transfers (ETs) and found that serum progesterone levels less than 15 ng/mL in the mid luteal phase had a negative impact on pregnancy outcome in both fresh and frozen ET cycles.[9]

Aims and Objectives:

The aim of this study was to determine if incrementing progesterone supplementation based on the levels of serum progesterone(P) measured on the day of ET has an impact on the pregnancy outcome in fresh and frozen ET cycles.


  Materials and methods Top


Source of data

A total of 220 women undergoing ET in both fresh and frozen cycles between February 2017 and August 2017 were enrolled in our study after obtaining written and informed consent. Out of these, 205 met the inclusion criterion and were included in our study group. Ethical clearance was obtained.

Design

This was a prospective cohort study.

Inclusion criterion

Patients less than 40 years undergoing ET (both fresh and frozen cycles) during the study period were included in our study.

Exclusion criterion

The exclusion criteria of the study were recurrent implantation failures, poor embryo quality, patients wherein a change in LPS was required due to inability to tolerate vaginal/injectable progesterone.

Methodology

GnRH antagonist protocol was followed in all the patients enrolled in our study. Dose of gonadotropins (rFSH [follitropin alpha or beta and highly purified HMG]) was decided based on the patient’s age, body mass index (BMI), ovarian reserve, and previous response. GnRH antagonist (Cetrolix Intas) was started according to the flexible protocol. Injection human chorionic gonadotropin 10,000 IU was given as the trigger in all the patients included in our study.


  Luteal support Top


LPS in the fresh ET cycles was vaginal micronized progesterone 400 mg twice a day and Injectable progesterone in oil 50 mg intramuscular twice a week.

In the frozen ET cycles LPS was vaginal micronized progesterone 400 mg twice a day and Injectable natural progesterone 50 mg intramuscular alternate day for patients with BMI less than 35. Injectable natural progesterone 50 mg intramuscular was given daily in cases having BMI more than 35.

Serum progesterone levels were measured on the day of ET after collecting 2cc of blood in plain vacutainer and analyzed after centrifugation using automated chemiluminescence microparticle immunoassay.

Patients undergoing fresh and frozen ETs were both divided into two groups based on serum progesterone levels on the day of ET. Group A1 included women who underwent a fresh ET and had serum progesterone less than 15 ng/mL on the day of ET, whereas group B1 included women undergoing a fresh ET with serum progesterone levels more than 15 ng/mL on the day of ET Group A2 and B2 included women who underwent frozen ET and had serum progesterone levels on the day of ET less than and more than 15 ng/mL, respectively [Figure 1].
Figure 1: Division of patients in two groups based on their serum progesterone levels on the day of transfer

Click here to view


If serum progesterone levels were found to be less than 15 ng/mL on the day of ET, the dose of progesterone supplementation was incremented (in fresh cycles we increased the dosage of injectable progesterone 50 mg from twice a week to 50 mg alternate days and in frozen cycles the dose of injectable progesterone was incremented to 50 mg daily from 50 mg alternate day) [Figure 2].
Figure 2: Protocol followed for division into subgroups based on serum progesterone and progesterone incrementation

Click here to view


A correlation between the groups with serum progesterone less than and more than 15 ng/mL on the day of ET with the pregnancy outcome was then made. Urine pregnancy test and βHCG were done 14 days after ET. A pregnancy test was considered positive if the βHCG levels exceeded 25 IU. Clinical pregnancy was defined by the presence of a gestation sac with fetal pole. Biochemical pregnancy was defined as a fall in βHCG levels without the appearance of a gestation sac.

Statistical analysis

Continuous variables are presented as mean ± standard deviation (SD), and categorical variables are presented as absolute numbers and percentage. For all statistical tests, chi-square tests were used for qualitative analysis and t test was used for comparison of means. All data analysis was carried out by the SPSS program for Windows, version 21.0. A value of P < 0.05 was taken to indicate a significant difference.

In fresh ET cycles we observed that there was no difference in the age, BMI, AMH, starting dose, the total days of stimulation, estrogen on the day of trigger, number of oocytes retrieved and the number of embryos transferred between the groups having progesterone less than 15 ng/mL (Group A1) and more than 15 ng/mL (Group B1) on the day of ET.

However, the progesterone level on the day of trigger was significantly lower in the group with progesterone less than 15 ng/mL [Table 1].
Table 1: Demographic profile of women undergoing fresh embryo transfer

Click here to view


In fresh ET cycles out of the 62 women recruited in the study eight patients had serum progesterone <15 ng/mL on the day of ET, which was incremented after the results of progesterone levels were obtained, whereas rest of the patients had progesterone more than 15 ng/mL (n = 54). No statistically significant difference was observed in the clinical pregnancy rate and biochemical pregnancies in group with progesterone less than or more than 15 ng/mL on the day of ET [Table 2].
Table 2: Pregnancy outcome in women undergoing fresh embryo transfer based on the serum progesterone levels on day of ET

Click here to view


In the frozen ET cycles, we did not find any difference in the age, BMI, and endometrial thickness between the two groups having progesterone less than 15 ng/mL (Group A2) and more than 15 ng/mL (Group B2) on the day of ET [Table 3].
Table 3: Demographic profile of women undergoing fresh embryo transfer

Click here to view


In the frozen ET cycle, out of the 143 women recruited 36 cases had progesterone less than 15 ng/mL on the day of ET which was incremented. No statistical significant difference was observed in the clinical pregnancy or biochemical pregnancies in the two groups [Table 4].
Table 4: Pregnancy outcome in women undergoing frozen embryo transfer based on the serum progesterone levels on day of ET

Click here to view



  Discussion Top


Serum progesterone assay has been proposed as a surrogate of endometrial competence and can help define a “fertile” luteal phase.[10] Progesterone induces a secretory transformation of the endometrium in the luteal phase which after adequate estrogen priming improves endometrial receptivity.[11] Decreased endometrial receptivity is considered largely responsible for the low implantation rates in IVF.[12]

Luteal phase of IVF-ET cycles is important as it might be the reason for the discrepancy between fertilization and pregnancy rates. Supplementation with progesterone may rescue potentially failing corpora lutea, thereby making the peri-implantation period more amiable to the implanting embryo.[13]

Liu et al.[14] showed in 341 patients undergoing ovarian stimulation for IVF that patients with viable pregnancies had significantly higher mean serum progesterone concentrations during the perimplantation period of the early luteal phase than patients who were not pregnant or had an early miscarriage.

Further, Mitwally et al.[15] in a study on 544 women undergoing IVF treatment also found a significant positive association between the mean serum progesterone concentration during the luteal phase and the clinical pregnancy outcome.

According to Humaidan et al.,[16] biochemical pregnancies were inversely correlated with the mid-luteal serum progesterone concentration showing a sharp decline in the early pregnancy loss from approximately 80% to 10% as the mid-luteal-phase progesterone concentration increases from approximately 40 nmol/l to approximately 80–100 nmol/L. Studies have shown that an early pregnancy losses (EPL) may result not only from chromosomally abnormal embryos, but also from malfunctions of the endometrium or both.

A study by Alsbjerg et al.[17] evaluated the reproductive outcome in patients who underwent frozen-thawed ET before and after doubling vaginal progesterone gel supplementation from 90 mg to 180 mg, resulting in a significant decrease in the EPL rate (67% vs. 44%, respectively; P = 0.014) and a significant increase in the delivery rate (9% vs. 21%, respectively; P = 0.002).

In a prospective cohort study conducted at our center during April 2016– December 2016, we analyzed the impact of midluteal serum progesterone levels on clinical pregnancy outcome. Patients with progesterone levels less than 15 ng/mL and more than 15 ng/mL during the midluteal phase in both fresh and frozen ET cycles were placed in two separate groups. In fresh ET cycles (n = 66), we observed that in the group with serum progesterone less than 15 ng/mL during the midluteal phase (n = 11) the pregnancy rate was 9% and in the group with progesterone levels more than 15 ng/mL (n = 55), the pregnancy rate was 40% (P = 0.049), thereby implying a negative effect of low midluteal serum progesterone levels on pregnancy outcome in fresh ET cycles. In the frozen ET cycles (n = 79), we found that in patients with progesterone levels less than 15 ng/mL (n = 21) and more than 15 ng/mL during the midluteal phase (n = 58) there was no statistical and clinical difference in the clinical pregnancy in patients with progesterone less than 15 ng/mL (47%) and those with progesterone >15 ng/mL (51.7%) in the midluteal phase (P = 0.74). However, in the frozen ET cycles we found a statistically significant increase in the biochemical pregnancies in the group with progesterone<15 ng/mL (P = 0.029) implying that low mid luteal progesterone levels in the frozen ET cycles might cause a detrimental effect on the pregnancy outcome. We thereby concluded that evaluation of serum progesterone in both fresh and frozen ET cycles may help identify patients who need additional LPS to improve the pregnancy outcome. Based on the findings of our study, we conducted this study and tried to analyze if measuring and incrementing progesterone early (before the midluteal phase) might improve our pregnancy outcomes.

In fresh ET cycles out of the 62 women recruited in the study eight patients had serum progesterone <15 ng/mL on the day of ET, which was incremented after the results of progesterone levels were obtained, whereas rest of the patients had progesterone more than 15 ng/mL (n = 54) and so they continued the standard LPS regimen. No statistically significant difference was observed in the clinical pregnancy rate and biochemical pregnancies in the group with progesterone less than or more than 15 ng/mL on the day of ET.

Similarly in our frozen ET cycle patients out of the 143 women recruited 36 cases had progesterone less than 15 ng/mL on the day of ET, which was incremented and again we did not find any difference in the clinical pregnancy rate or biochemical pregnancies in the two groups stressing the importance of measuring and incrementing progesterone early in the cycle.

Ellenbogen et al.[18] assessed 224 IVF cycles and found that mid-luteal progesterone concentrations were significantly higher (15.3 ± 4.9 ng/mL vs. 12.9 ± 4.9 ng/mL, P < 0.002) in patients who became pregnant compared with those who did not. In pregnant patients, 53% had mid-luteal progesterone exceeding 15 ng/mL vs. 31% in nonpregnant patients (P < 0.01).

The same group did a prospective RCT in 2017 to establish whether increasing progesterone dosage for patients with low levels at mid-luteal phase may improve pregnancy rates. They included a total of 146 patients undergoing IVF treatment and measured serum progesterone levels 7 days after ET and increased the progesterone support in patients with serum progesterone levels less than 15 ng/mL. However, they found that mid-luteal intervention by increasing progesterone support did not improve cycle outcomes. The probable reason for the same could be the delayed increase in the dose of progesterone supplementation. This study also suggested that assessing progesterone levels earlier in the implantation window may be beneficial for adjustment of the optimal dosage. The limitation of this study was also that they recruited women undergoing different stimulation protocols; however, in our study all women underwent the GnRH antagonist protocol.[19]

A study done by Alvarenz et al.[20] in which 574 HRT FET cycles were included where progesterone levels were measured the day prior to euploid FET. Serum progesterone levels  more than 10.6 ng/mL were considered as adequate and euploid FET was performed on the following day, whereas Pl levels  < 10.6 ng/mL was considered as low, iLPS was added in the form of daily Psc injections, and a new P analysis was performed on the following day. FET was only performed on the same day when a restored P > 10.6 ng/mL was achieved (98.2% of cases), thereby suggesting an “opportunity window” for improved ongoing pregnancy rates and miscarriage rates in cases of inadequate P levels the day previous to FET. The same group did a similar study even in women undergoing NC FET and found mean serum P levels on the day before FET were significantly higher in patients who had a live birth compared to those who did not (14.5 ± 7.0 vs. 12.0 ± 6.6 ng/mL, 95% CI [0.83; 4.12]).[21]

Lambarta et al.[22] did a prospective cohort study with 244 patients who underwent ET in an oocyte donation cycle after an artificial endometrial preparation cycle with estradiol valerate and vaginal micronized progesterone 400 mg bd. Patients with serum P < 9.2 ng/mL on the day of ET had a significantly lower OPR suggesting a minimum threshold of serum P values on the day of ET that needs to be reached in artificial endometrial preparation cycles to optimize pregnancy outcome. The same group did a study in women undergoing FET in self and donor oocyte cycles (n = 1150) and found that women with serum P levels <8.8 ng/mL had a significantly lower ongoing pregnancy rate (36.6% vs. 54.4%) and live birth rate (35.5% vs. 52.0%) when using micronized vaginal progesterone in a dose of 400 mg bd as LPS. One-third of their patients showed inadequate levels of serum P which impacted the success of the ART cycle, thereby they suggested monitoring P levels in the mid-luteal phase is recommended when using MVP for dose adjustments to optimize pregnancy outcomes.[23]

The interest on the impact of serum P levels during window of implantation has emerged in the last years. There seems to be a relationship between low serum P levels and poorer outcome, in terms of ongoing pregnancy or live birth rate. We incremented our progesterone levels early in the cycle aiming to have adequate progesterone levels during the window of implantation as increasing it later in the cycle might not be of much benefit as the window of implantation (WOI) would have already closed.

Another interesting finding in our study was the statistically significant lower levels of progesterone on the day of trigger in the patient group with low progesterone levels (<15 ng/mL) on the day of ET in fresh cycles. A study done by Santos et al.[24] states that low “hCG-trigger-day” P values (<0.5 ng/mL) results in lower live birth rates and the reason for the same as proposed by them could be luteinization defect. They suggested that a more intense or earlier LPS could counter-balance the negative influence of low Progesterone on the live birth rates.


  Conclusion Top


Measuring serum progesterone levels on the day of ET and incrementing if levels of progesterone are less than 15 ng/mL to obtain optimal progesterone levels during the WOI in both fresh and frozen ET cycles might help in improving our pregnancy outcomes.

Financial support and sponsorship

Not applicable.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Yanushpolsky EH Luteal phase support in in vitro fertilization. Semin Reprod Med 2015;33:118-27.  Back to cited text no. 1
    
2.
Fatemi HM, Popovic-Todorovic B, Papanikolaou E, Donoso P, Devroey P An update of luteal phase support in stimulated IVF cycles. Hum Reprod Update 2007;13:581-90.  Back to cited text no. 2
    
3.
Van Steirteghem AC, Smitz J, Camus M, Van Waesberghe L, Deschacht J, Khan I, et al. The luteal phase after in vitro fertilization and related procedures. Hum Reprod 1988;3:161-4.  Back to cited text no. 3
    
4.
Yding Andersen C, Vilbour Andersen K Improving the luteal phase after ovarian stimulation: Reviewing new options. Reprod Biomed Online 2014;28:552-9.  Back to cited text no. 4
    
5.
Wetendorf M, DeMayo FJ The progesterone receptor regulates implantation, decidualization, and glandular development via a complex paracrine signaling network. Mol Cell Endocrinol 2012;357:108-18.  Back to cited text no. 5
    
6.
Druckmann R, Druckmann MA Progesterone and the immunology of pregnancy. J Steroid Biochem Mol Biol 2005;97:389-96.  Back to cited text no. 6
    
7.
Simoncini T, Caruso A, Giretti MS, Scorticati C, Fu XD, Garibaldi S, et al. Effects of dydrogesterone and of its stable metabolite, 20-alpha-dihydrodydrogesterone, on nitric oxide synthesis in human endothelial cells. Fertil Steril 2006;86:1235-42.  Back to cited text no. 7
    
8.
Szekeres-Bartho J, Wilczynski JR, Basta P, Kalinka J Role of progesterone and progestin therapy in threatened abortion and preterm labour. Front Biosci 2008;13:1981-90.  Back to cited text no. 8
    
9.
Kaur J, Naidu P, Kumkum R, Mahajan N Impact of mid-luteal serum progesterone levels on pregnancy outcome in fresh and frozen embryo transfer cycles in women of Indian ethnicity. The Onco Fertility Journal 2018;1:30.  Back to cited text no. 9
    
10.
Jordan J, Craig K, Clifton DK, Soules MR Luteal phase defect: The sensitivity and specificity of diagnostic methods in common clinical use. Fertil Steril 1994;62:54-62.  Back to cited text no. 10
    
11.
Kolibianakis EM, Bourgain C, Platteau P, Albano C, Van Steirteghem AC, Devroey P Abnormal endometrial development occurs during the luteal phase of nonsupplemented donor cycles treated with recombinant follicle-stimulating hormone and gonadotropin-releasing hormone antagonists. Fertil Steril 2003;80:464-6.  Back to cited text no. 11
    
12.
Doody K, Shamma FN, Paulson RJ, Bayer S, Blake E, Yankov VI Endometrin for luteal phase support in a randomized, controlled, open- label, prospective IVF clinical trial using a combination of Menopur and Bravelle. Fertil Steril 2007;87(S2):S24.  Back to cited text no. 12
    
13.
Daya S Efficacy of progesterone support in the luteal phase following in-vitro fertilization and embryo transfer: Meta-analysis of clinical trials. Hum Reprod 1988;3:731-4.  Back to cited text no. 13
    
14.
Liu HC, Pyrgiotis E, Davis O, Rosenwaks Z Active corpus luteum function at pre-, peri- and postimplantation is essential for a viable pregnancy. Early Pregnancy 1995;1:281-7.  Back to cited text no. 14
    
15.
Mitwally MF, Diamond MP, Abuzeid M Vaginal micronized progesterone versus intramuscular progesterone for luteal support in women undergoing in vitro fertilization-embryo transfer. Fertil Steril 2010;93:554-69.  Back to cited text no. 15
    
16.
Humaidan P, Bungum L, Bungum M, Yding Andersen C Rescue of corpus luteum function with peri-ovulatory HCG supplementation in IVF/ICSI GnRH antagonist cycles in which ovulation was triggered with a GnRH agonist: A pilot study. Reprod Biomed Online 2006;13:173-8.  Back to cited text no. 16
    
17.
Alsbjerg B, Polyzos NP, Elbaek HO, Povlsen BB, Andersen CY, Humaidan P Increasing vaginal progesterone gel supplementation after frozen-thawed embryo transfer significantly increases the delivery rate. Reprod Biomed Online 2013;26:133-7.  Back to cited text no. 17
    
18.
Ellenbogen A, Gidoni Y, Michaeli M, Rotfarb N, Ballas S Mid-luteal serum progesterone and estradiol levels as predictors of pregnancy in IVF-ET cycles: May increasing the dosage of progesterone supplementation improve the outcome? Fertil Steril 2004;82:S205-6.  Back to cited text no. 18
    
19.
Aslih N, Ellenbogen A, Shavit T, Michaeli M, Yakobi D, Shalom-Paz E Can we alter pregnancy outcome by adjusting progesterone treatment at mid-luteal phase: A randomized controlled trial. Gynecol Endocrinol 2017;33:602-6.  Back to cited text no. 19
    
20.
Álvarez M, Gaggiotti-Marre S, Martínez F, Coll L, García S, González-Foruria I, et al. Individualised luteal phase support in artificially prepared frozen embryo transfer cycles based on serum progesterone levels: A prospective cohort study. Hum Reprod 2021;36:1552-60.  Back to cited text no. 20
    
21.
Gaggiotti-Marre S, Álvarez M, González-Foruria I, Parriego M, Garcia S, Martínez F, et al. Low progesterone levels on the day before natural cycle frozen embryo transfer are negatively associated with live birth rates. Hum Reprod 2020;35:1623-9.  Back to cited text no. 21
    
22.
Labarta E, Mariani G, Holtmann N, Celada P, Remohí J, Bosch E Low serum progesterone on the day of embryo transfer is associated with a diminished ongoing pregnancy rate in oocyte donation cycles after artificial endometrial preparation: A prospective study. Hum Reprod 2017;32:2437-42.  Back to cited text no. 22
    
23.
Labarta E, Mariani G, Paolelli S, Rodriguez-Varela C, Vidal C, Giles J, et al. Impact of low serum progesterone levels on the day of embryo transfer on pregnancy outcome: A prospective cohort study in artificial cycles with vaginal progesterone. Hum Reprod 2021;36:683-92.  Back to cited text no. 23
    
24.
Santos-Ribeiro S, Polyzos NP, Haentjens P, Smitz J, Camus M, Tournaye H, et al. Live birth rates after IVF are reduced by both low and high progesterone levels on the day of human chorionic gonadotrophin administration. Hum Reprod 2014;29:1698-705.  Back to cited text no. 24
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

Top
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
Abstract
Introduction
Materials and me...
Luteal support
Discussion
Conclusion
References
Article Figures
Article Tables

 Article Access Statistics
    Viewed238    
    Printed2    
    Emailed0    
    PDF Downloaded20    
    Comments [Add]    

Recommend this journal