Systematic Review of Ovarian Activity and Potential for Embryo Formation and Loss during the Use of Hormonal Contraception

The effect of uterine entry technique on chorioamniotic membrane separation in fetoscopic laser photocoagulation for twin-to-twin transfusion syndrome: protocol for a randomized controlled trial

Burnett BA et al., 2025 · BMC pregnancy and childbirth · Free full text on PubMed Central

Surgery in Restorative Reproductive Medicine

Yeung P, 2025 · J Restorative Reprod Med · Free to read

Restorative reproductive surgery has emerged to become an exciting and promising field of surgery that can transform the way that we treat patients, especially regarding fertility. As a prime example of this type of surgery, restorative reproductive surgery for endometriosis, a common and debilitating disease that can lead to infertility and pelvic pain, offers a root cause treatment to remove the actual disease and to optimize the reproductive anatomy, for best patient outcomes. Optimal excision of endometriosis and prevention of pelvic adhesions has been shown to lead to reduce symptoms, to lead to high natural fertility rates, and to lead to very low rates of the need for repeat surgery. Patients have improved symptoms and quality of life, in addition to improved fertility chances for one and subsequent pregnancies (if desired), demonstrating the link between wellness and fertility. There is an urgent need for more resources, training, advocacy, research and publication for this exciting area of restorative reproductive surgery. Its time has come.

The Long-term Rate of Repeat Surgery After Optimal Excision Surgery of Endometriosis at a Single Tertiary Referral Center

Yeung P et al., 2025 · Acta Scientific Women's Health · Free to read

The primary purpose of this prospective cohort study was to determine if treating endometriosis with optimal excision surgery leads to lower rates of repeat surgery as compared to historical rates of repeat surgery by ablation. A secondary outcome was to examine whether the use of hormonal suppression differed before surgery, depending on the stage of endometriosis found at surgery. Optimal excision was defined as completely excising all areas of abnormal peritoneum, wherever found in the pelvis, having looked systematically with near contact laparoscopy. All surgeries were performed by a single surgeon specializing in optimal excision at a tertiary referral center. The rate of repeat surgery after optimal excision surgery for endometriosis was remarkably low (2.5%, 15/620) as compared to historical rates of repeat surgery by ablation. Additionally, the lack of significant evidence between hormonal suppression use and progression of stage of endometriosis provides implicit evidence that hormonal suppression does not prevent progression of the disease. Further controlled studies are needed to verify these findings.

Outcomes of fetal lower urinary tract obstruction based on timing of oligohydramnios onset

Munoz JL et al., 2023 · Prenat Diagn

Fetal Lower Urinary Tract Obstruction (LUTO) is associated with oligohydramnios and significant fetal morbidity, resulting in poor lung development and perinatal death. However, oligohydramnios may develop at different gestational periods, and the impact of timing on fetal outcomes remains unknown. Our objective was to characterize the impact onset of oligohydramnios had on prenatal outcomes. This study is a retrospective cohort study of all patients with a prenatal diagnosis of LUTO at our tertiary referral center from 2014 to 2023. All patients underwent detailed ultrasonography and interdisciplinary counseling and were subsequently delivered at our institution. Data were obtained from electronic medical records and complete extraction was required for final inclusion. During the study time period, 93 patients met inclusion criteria of which 68 (73.1%) developed oligohydramnios during their pregnancy. 63 (93%) of these pregnancies resulted in livebirths with 28 (41.1%) perinatal deaths. Onset of oligohydramnios was earlier in pregnancies with perinatal death (23 vs. 28 weeks, p = 0.004) and associated with pulmonary hypoplasia. Our data show the impact of oligohydramnios timing in pregnancy on pulmonary hypoplasia and ultimately perinatal death. This allows for detailed patient counseling on the impact oligohydramnios may have on pregnancies by the gestational age of onset.

Does levonorgestrel emergency contraceptive have a post-fertilization effect? A review of its mechanism of action

Peck R et al., 2016 · Linacre Q · Free full text on PubMed Central

Recent studies have identified that levonorgestrel administered orally in emergency contraception (LNG-EC) is only efficacious when taken before ovulation. However, the drug does not consistently prevent follicular rupture or impair sperm function. The present systematic review is performed to analyze and more precisely define the extent to which pre-fertilization mechanisms of action may explain the drug's efficacy in pregnancy avoidance. We also examine the available evidence to determine if pre-ovulatory drug administration may be associated with post-fertilization effects. The mechanism of action of LNG-EC is reviewed. The drug has no ability to alter sperm function at doses used in vivo and has limited ability to suppress ovulation. Our analysis estimates that the drug's ovulatory inhibition potential could prevent less than 15 percent of potential conceptions, thus making a pre-fertilization mechanism of action significantly less likely than previously thought. Luteal effects (such as decreased progesterone, altered glycodelin levels, and shortened luteal phase) present in the literature may suggest a pre-ovulatory induced post-fertilization drug effect. Plan B is the most widely used emergency contraceptive available. It is important for patients and physicians to clearly understand the drug's mechanism of action (MOA). The drug was originally thought to work by preventing fertilization. Recent research has cast doubt on this. Our review of the research suggests that it could act in a pre-fertilization capacity, and we estimate that it could prevent ovulation in only 15 percent or less of cases. The drug has no ability to alter sperm function and limited ability to suppress ovulation. Further, data suggest that when administered pre-ovulation, it may have a post-fertilization MOA.

Levonorgestrel emergency contraception: a joint analysis of effectiveness and mechanism of action

Mikolajczyk RT et al., 2007 · Fertil Steril

To model the effectiveness that can be obtained if levonorgestrel-only emergency contraception (EC) acts only through disrupting ovulation, in relation to other effects that may occur before or after fertilization and accounting for delays in administration. We modeled follicular growth as a function of follicular size, using known day-specific probabilities of conception and known disruption of ovulation by levonorgestrel-only EC, to estimate the expected effectiveness of EC. Combined data from multiple clinical studies. PATIENT(S): Simulation models. INTERVENTION(S): Disruption of ovulation. MAIN OUTCOME MEASURE(S): Effectiveness in the form of proportion of pregnancies prevented. RESULT(S): With disruption of ovulation alone, the potential effectiveness of levonorgestrel EC ranged from 49% (no delay) to 8% (72-hour delay). With complete inhibition of fertilization before the day of ovulation, the potential effectiveness of levonorgestrel EC ranged from 90% (no delay) to 16% (72-hour delay). CONCLUSION(S): The gap between effectiveness of levonorgestrel EC estimated from clinical studies and what can be attributed to disruption of ovulation may be explained by overestimation of actual effectiveness and supplementary mechanisms of action, including postfertilization effects. Additional data with follicular ultrasound and precise measures of delay between intercourse and EC administration would yield greater insight into effectiveness and mechanisms of action.

Postfertilization effect of hormonal emergency contraception

Kahlenborn C et al., 2002 · Ann Pharmacother

To assess the possibility of a postfertilization effect in regard to the most common types of hormonal emergency contraception (EC) used in the US and to explore the ethical impact of this possibility. DATA A MEDLINE search (1966-November 2001) was done to identify all pertinent English-language journal articles. A review of reference sections of the major review articles was performed to identify additional articles. Search terms included emergency contraception, postcoital contraception, postfertilization effect, Yuzpe regimen, levonorgestrel, mechanism of action, Plan B. The 2 most common types of hormonal EC used in the US are the Yuzpe regimen (high-dose ethinyl estradiol with high-dose levonorgestrel) and Plan B (high-dose levonorgestrel alone). Although both methods sometimes stop ovulation, they may also act by reducing the probability of implantation, due to their adverse effect on the endometrium (a postfertilization effect). The available evidence for a postfertilization effect is moderately strong, whether hormonal EC is used in the preovulatory, ovulatory, or postovulatory phase of the menstrual cycle. Based on the present theoretical and empirical evidence, both the Yuzpe regimen and Plan B likely act at times by causing a postfertilization effect, regardless of when in the menstrual cycle they are used. These findings have potential implications in such areas as informed consent, emergency department protocols, and conscience clauses.

Systematic Review of Postfertilization Effects and Potential for Embryo Formation and Loss during the Use of Intrauterine Devices

Buskmiller C et al., 2020 · Linacre Q · Free full text on PubMed Central

This review sought to evaluate the evidence for embryo formation during intrauterine device (IUD) use, to articulate how often embryo loss occurs in well-designed studies, and to comment on other bodies of literature suggestive of postfertilization mechanisms of action of IUDs. The MEDLINE, EMBASE, and Ovid databases were searched for English-language studies of markers of pregnancy in IUD users in May 2018. Studies of human chorionic gonadotropin (hCG) were subjected to quality assessment based on the US Preventive Services Task Force quality tool. Bias of studies assessing pregnancy in other ways was assessed on a study-to-study basis. In all, 1,073 studies were identified and 138 were read in detail. Twenty-three studies of β-hCG, 4 studies of direct observation of embryos in fallopian tubes, 2 studies of pregnancy-specific binding globulin (PSBG), and 1 study of heat-shock protein 10 (Hsp10) or chaperonin 10 were included. In all studies considered together, 7.3 percent of IUD users had evidence of fertilization and pregnancy failure. In good-quality studies, 4.5 percent had evidence of fertilization and pregnancy failure. There are no randomized trials of embryo formation and loss in IUD users compared with noncontracepting controls. Studies of β-hCG span a large spectrum of quality, but several good-quality studies exist, which support embryo formation and loss in IUD users. Evidence of embryos found in tubes is moderate and evidence of PSBG and Hsp10 elaboration was limited, but these are also concerning for embryo formation and loss. There is good-quality evidence of embryo formation and loss in IUD users. Studies are inconsistent, and the stated conclusions of several papers inaccurately diminish postfertilization evidence of embryo formation. To better assess the rate of embryo loss in IUD users compared with non-users, future research should include well-designed prospective trials and less subjective assessments of embryos in fallopian tubes. A systematic review was carried out examining the English-language literature in the MEDLINE, EMBASE, and Ovid databases for evidence of embryo formation and loss during IUD use. In all, 1,073 studies were identified and 138 were read. There are no randomized trials and evidence ranges in quality, but evidence for the embryo formation and loss in 4.5 percent of IUD users exists in good-quality research. Further research is needed to compare embryo loss in IUD users to loss in controls.