Risk Of Miscarriage In Pregnancy Research Articles

Cesarean section at full dilatation in the first birth is not associated with an increased risk of subsequent miscarriage: A historical cohort study.

Cesarean section at full dilatation has been associated with an increased risk of subsequent preterm birth. We hypothesized that there may be an increased risk of miscarriage in pregnancies that follow cesarean section at full dilatation. This study aimed to determine if a first-term (≥37 weeks) cesarean section at full dilatation is associated with an increased risk of miscarriage in the next pregnancy. A historical cohort study was conducted using routinely collected hospital data within the Aberdeen Maternity and Neonatal Databank (AMND). The population included were women who had a first-term birth and who had a second birth recorded within the AMND. Logistic and multinomial regression was used to determine any association with miscarriage at any gestation and for early (<13 weeks gestation) and late (13-23 + 6 weeks gestation) miscarriage, with cesarean section at full dilatation defined as the exposure. Miscarriage in the second pregnancy (spontaneous loss of intrauterine pregnancy prior to 24 weeks gestation) was the primary outcome. In total, 33 452 women were included. Women who had a first cesarean section at full dilatation were no more likely to have a miscarriage at any gestation than women with all other modes of first birth (including all vaginal births, planned CS, and the first stage of labor (<10 cm dilated CS)) [adjusted OR 0.84 (0.66-1.08); p = 0.18]. There was no association with early or late miscarriage after a CSfd, though the sample size for late miscarriage was small. This is the first observational study to investigate the risk of miscarriage following first-term CSfd. We found no association between miscarriage at any gestation following a first-term CSfd compared to all other modes of first birth.

Low ovarian reserve and risk of miscarriage in pregnancies derived from assisted reproductive technology.

Do low levels of anti-Müllerian hormone (AMH) or antral follicle count (AFC) properly predict miscarriage in young women conceiving with ART? Low ovarian reserve, as indicated by AMH or AFC, is not associated with miscarriage in young women conceiving with ART. Presently, the impact of low ovarian reserve on the risk of miscarriage remains controversial. Some studies have reported an association between serum AMH levels and AFC and miscarriage, but others have failed to confirm these findings. The main limitation that undermines the reliability and consistency of the results is the confounding effect of female age. Indeed, after 35 years of age, on the one hand, the risk of miscarriage starts increasing because of impaired oocyte quality while, on the other, the physiological decline in AMH and AFC levels continues, thus hampering the possibility to properly explore the real effects of reduced ovarian reserve. Indeed, the two processes, i.e. the gradual loss of resting primordial follicles and the loss of oocyte quality, progress in parallel. In other words, the older the woman becomes, the higher is the risk of miscarriage, but one cannot distinguish between the effects of biological aging on oocyte quality and those mediated by a lower ovarian reserve. The present retrospective monocentric cohort study was carried out at Fondazione IRCSS Ca Granda Ospedale Maggiore Policlinico, Milan. All women referred to the ART Unit between 2014 and 2021 and who underwent either conventional IVF (c-IVF), ICSI, or IUI were reviewed. Only women younger than 35 were eligible because, up to this age, the risk of miscarriage is steady and not strictly related to age. Women younger than 35 who achieved a singleton clinical pregnancy with c-IVF, ICSI, or IUI were selected. Women with patent causes of recurrent miscarriage were excluded, as well as those undergoing pregnancy termination for fetal or medical causes. Women who did and did not have a pregnancy loss before 20 weeks' gestation were compared. Detailed information was obtained from charts of the consulting patients. ART procedures were performed according to the standardized policy of our Unit. All women underwent serum AMH measurement and a transvaginal assessment of AFC prior to initiation of treatment. AMH levels were measured by a commercially available ELISA assay. To assess AFC, all identifiable antral follicles 2-10 mm in diameter at ultrasound were recorded. The primary outcome was the risk of miscarriage for women with serum AMH levels below 5 pmol/l. There were 538 women were included, of whom 92 (17%) had a miscarriage. The areas under the ROC curves for prediction of miscarriage based on AMH levels and AFC were 0.51 (95% CI: 0.45-0.58) and 0.52 (95% CI: 0.45-0.59), respectively. The odds ratio (OR) of miscarriage for women with serum AMH levels below 5.0 pmol/l was 1.10 (95% CI: 0.51-2.36); the adjusted OR was 1.12 (95% CI: 0.51-2.45). Analyses were repeated considering other thresholds for AMH (2.9, 3.6 and 7.9 pmol/l) and for AFC (thresholds of 7 and 10). No associations emerged. The retrospective design of the study hampered the collection of more precise but potentially relevant clinical information of the couples. We did not exclude women suffering from PCOS, a condition possibly associated with miscarriage. Moreover, the baseline characteristics of women who did and did not have a miscarriage differed in some characteristics. Thus, we adjusted the OR using a multivariate analysis, but we cannot fully exclude residual confounding effects. Finally, our results cannot be inferred to women older than 35. The mechanisms causing premature exhaustion of ovarian reserve may be different in younger and older women and this may lead to a different impact on the risk of miscarriage. Women embarking on ART with low ovarian reserve should be informed of their likely poor response to ovarian stimulation but can be reassured that, if conception occurs, their risk of miscarriage is not increased. This study was partially funded by Italian Ministry of Health-Current research IRCCS. E.S. reports grants from Ferring and honoraria for lectures from Merck-Serono and Gedeon-Richter. All the other authors do not have any competing interest to declare. N/A.

First-trimester miscarriage rate decreases with hydralazine therapy in pregnancies with early uterine vascular insufficiency: a cohort study

Background Miscarriage is the most frequent cause of pregnancy loss, affecting 15–20% of clinically recognized pregnancies. Early uterine vascular insufficiency (EUVI), defined as abnormal uterine artery (UA) Doppler impedance indices in early pregnancy, is present in two-thirds of pregnancies ending in miscarriage after embryonic cardiac activity has been detected. There is currently no available therapy for reducing the risk of miscarriage in these cases. Objective To determine whether vasodilator therapy with hydralazine can reduce abnormally high UA impedance indices and miscarriage rates in pregnancies with EUVI when administered from before 9 weeks’ gestation until completing 13 weeks’ gestation. Methods A total of 253 consecutive singleton pregnancies with a live embryo and scanned before 9 weeks’ gestation were included in the study. Ninety-two pregnancies (36.3%) were classified as having EUVI. Hydralazine was administered in daily doses of 50 mg, starting 24–36 h after the initial diagnosis of EUVI and continuing throughout the first trimester. The miscarriage rate in the hydralazine-treated EUVI group was compared with the one observed in our previously reported untreated cohort and the pregnancies with EUVI that declined treatment with hydralazine. Results The miscarriage rate among the hydralazine-treated EUVI group was significantly lower than the previously reported untreated cohort (7.8% versus 26.2%, p = .003; odds ratio (OR) = 4.3, 95% confidence interval (CI) = 1.6–11.9). In 15 untreated pregnancies with EUVI, the miscarriage rate was similar to that of the previously reported untreated cohort (26.7% versus 26.2%; p = .603) and higher than the hydralazine-treated group (26.7% versus 7.8%, p = .05; OR = 4.4, 95% CI = 1.1–18.2). Conclusions Hydralazine therapy in pregnancies with EUVI was associated with a significant decrease in the rate of miscarriage. We suggest a sequence of events leading to a higher risk of miscarriage in pregnancies with EUVI and propose a potential mechanism through which hydralazine may reduce this risk.

Risk of Fetal Loss in Pregnancies Undergoing Midtrimester Amniocentesis after Inconclusive Chorionic Villus Sampling

Objective: To estimate the procedure-related risk of miscarriage in pregnancies undergoing amniocentesis (AC) following inconclusive results for a chorionic villus sampling (CVS). Methods: This was a multicentric retrospective cohort study of patients in which both CVS at 11–13 weeks’ gestation and AC at 16–22 weeks were performed between January 1st, 2008, and July 31st, 2017. The primary outcome measure was pregnancy loss prior to 24 weeks gestation; the secondary one was intrauterine demise after 24 weeks. Results: A total of 287 patients underwent transabdominal CVS and AC. Nine patients were lost at follow-up; therefore, the analysis was conducted on a population of 278 patients (275 singletons and 3 dichorionic twin pregnancies). AC was performed because of placental mosaicism (93.6%), failure of direct/semidirect preparation of trophoblastic cells (3.2%), or targeted genetic testing after the diagnosis of an anomaly in the second trimester (3.2%). In continuing pregnancies, there were no fetal losses prior to 24 weeks’ gestation. Two intrauterine demises (including 1 fetus with multiple anomalies and growth restriction) in the third trimester were recorded. Conclusion: Patients undergoing midtrimester AC because of an inconclusive result of CVS can be reasonably reassured that in general the risk of miscarriage and fetal loss following the procedure is very small.

There is no association between the presence of anti-thyroid antibodies and increased reproductive loss in pregnant women after ART: a systematic review and meta-analysis.

Women submitted to ART treatments represent a select subgroup of individuals. Several studies have described the relationship between TAI and pregnancy outcomes as a result of ART, with contradictory results. The purpose of this systematic review was to determine the association between TAI and the risk of miscarriage in pregnancies resulting from ART. MEDLINE via PubMed, LILACS and Embase were searched for studies published in peer-reviewed journals from 1999 to 2017. The studies were summarized using the fixed effects model and the Peto's method to calculate RR in order to flesh out the association between TAI and spontaneous abortion. Only four papers were included in this systematic review and meta-analysis. Thirty-one miscarriages were observed in 210 clinical pregnancies of women with antithyroid antibodies; and 158 miscarriages were seen in 1,371 pregnancies without antithyroid antibodies. The meta-analysis failed to find an association between TAI and higher risk of reproductive loss, RR=0.94 95% confidence interval: 0.71-1.24; p=0.879. In conclusion, the presence of antithyroid antibodies was not associated with increased reproductive loss in patients submitted to ART treatments. It is our opinion that the presence of antithyroid antibodies should be considered as a secondary biomarker of autoimmune disease, rather than an actual cause of miscarriage in patients undergoing ART. Due to the small amount of evidence on the matter, the determination of TAI before the initiation of ART should be limited to research contexts.