Second trimester dilation and evacuation: a risk factor for preterm birth?

Impact of first-trimester mechanical cervical dilatation during curettage on maternal and neonatal outcomes: A retrospective comparative study

OBJECTIVE

Earlier studies have indicated a potential link between dilatation and curettage (D&C) and subsequent preterm delivery, possibly attributed to cervical damage. This study examines outcomes in pregnancies subsequent to first-trimester curettage with and without cervical dilatation.

METHODS

A retrospective cohort study was conducted on women who conceived after undergoing curettage due to a first trimester pregnancy loss. Maternal and neonatal outcomes of the subsequent pregnancy were compared between two groups: women who underwent cervical dilatation before their curettage and those who had curettage without dilatation. The primary outcome assessed was the rate of preterm delivery at the subsequent pregnancy, and secondary outcomes included other adverse maternal and neonatal outcomes. Univariate analysis was performed, followed by multiple logistic regression models to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs).

RESULTS

Among the 1087 women meeting the inclusion criteria during the study period, 852 (78.4 %) underwent first-trimester curettage with cervical dilatation, while 235 (21.6 %) opted for curettage only. No significant maternal or neonatal different outcomes were noted between the study groups, including preterm delivery (5.5 % vs. 3.5 %, p = 0.16), fertility treatments, placental complications, and mode of delivery. However, deliveries following D&C were associated with higher rates of small for gestational age neonates (7.6 % vs. 3.8 %, p = 0.04). Multivariate analysis revealed that cervical dilation before curettage was not significantly linked to preterm delivery [adjusted odds ratio 0.64 (0.33-1.26), p = 0.20].

CONCLUSION

The use of cervical dilatation during a curettage procedure for first trimester pregnancy loss, does not confer additional risk of preterm delivery. Further studies are needed to reinforce and validate these results.

Is a pregnancy following a second trimester uterine evacuation associated with increased adverse maternal and neonatal outcomes?

OBJECTIVE

To evaluate maternal and neonatal outcomes of pregnancies following a uterine evacuation in the second trimester, in comparison to a first trimester spontaneous pregnancy loss.

STUDY DESIGN

A retrospective analysis of data of women who conceived ≤6 months following a uterine evacuation due to a spontaneous pregnancy loss and subsequently delivered in a single tertiary medical center between 2016 and 2021. Maternal and neonatal outcomes were compared between women with second trimester (14-23 weeks) and first trimester (<14 weeks) pregnancy loss. The primary outcome of this study was the preterm delivery (<37 weeks) rate. Secondary outcomes were adverse maternal and neonatal outcomes. Univariate analysis was followed by multiple logistic regression models; adjusted odds ratios (aORs) and 95 % confidence intervals (CIs) were calculated.

RESULTS

During the study period, 1365 women met the inclusion criteria. Of those, 272 (19.9 %) women gave birth following a second trimester uterine evacuation and 1093 (80.1 %) women following a first trimester uterine evacuation. There were no demographic differences between the two groups. No difference was found in the preterm delivery rate in the subsequent pregnancy (5.1 % vs. 5.3 %, p = 0.91), further confirmed in the multivariate analysis [aOR 1.02 (0.53-1.94), p = 0.96]. No differences were identified with respect to other maternal and neonatal parameters examined, including hypertension disorders of pregnancy, third stage placental complications, mode of delivery and neonatal birth weight.

CONCLUSION

Pregnancy conceived shortly after second trimester uterine evacuation as compared to first trimester, confers no additional risk for preterm delivery or other adverse perinatal outcomes. Further studies to strengthen these findings are needed.

Subgroup identification of early preterm birth (ePTB): informing a future prospective enrichment clinical trial design

BACKGROUND

Despite the widely recognized association between the severity of early preterm birth (ePTB) and its related severe diseases, little is known about the potential risk factors of ePTB and the sub-population with high risk of ePTB. Moreover, motivated by a future confirmatory clinical trial to identify whether supplementing pregnant women with docosahexaenoic acid (DHA) has a different effect on the risk subgroup population or not in terms of ePTB prevalence, this study aims to identify potential risk subgroups and risk factors for ePTB, defined as babies born less than 34 weeks of gestation.

METHODS

The analysis data (N = 3,994,872) were obtained from CDC and NCHS' 2014 Natality public data file. The sample was split into independent training and validation cohorts for model generation and model assessment, respectively. Logistic regression and CART models were used to examine potential ePTB risk predictors and their interactions, including mothers' age, nativity, race, Hispanic origin, marital status, education, pre-pregnancy smoking status, pre-pregnancy BMI, pre-pregnancy diabetes status, pre-pregnancy hypertension status, previous preterm birth status, infertility treatment usage status, fertility enhancing drug usage status, and delivery payment source.

RESULTS

Both logistic regression models with either 14 or 10 ePTB risk factors produced the same C-index (0.646) based on the training cohort. The C-index of the logistic regression model based on 10 predictors was 0.645 for the validation cohort. Both C-indexes indicated a good discrimination and acceptable model fit. The CART model identified preterm birth history and race as the most important risk factors, and revealed that the subgroup with a preterm birth history and a race designation as Black had the highest risk for ePTB. The c-index and misclassification rate were 0.579 and 0.034 for the training cohort, and 0.578 and 0.034 for the validation cohort, respectively.

CONCLUSIONS

This study revealed 14 maternal characteristic variables that reliably identified risk for ePTB through either logistic regression model and/or a CART model. Moreover, both models efficiently identify risk subgroups for further enrichment clinical trial design.

Update on second-trimester surgical abortion

PURPOSE OF REVIEW

To review the recent literature on surgical second-trimester abortion, with specific attention to cervical preparation techniques.

RECENT FINDINGS

Confirming previous studies, a recent retrospective observational cohort study, including 54 911 abortions, estimated the total abortion-related complication rate to be 0.41% for second-trimester or later procedures. Cervical preparation is known to reduce risks associated with second-trimester dilation and evacuation (D&E). When considering adjuncts to osmotic dilators for cervical preparation prior to D&E after 16 weeks, both misoprostol and mifepristone are effective alone and in combination or as adjuncts to osmotic dilators. Misoprostol consistently has been shown to cause more pain and cramping than placebo, but is an effective adjunct to osmotic dilators after 16 weeks. Although mifepristone has fewer side-effects, at its current price, it may not be as cost-effective as misoprostol.

SUMMARY

Second-trimester abortion is safe. The use of mifepristone and misoprostol for second-trimester abortion has improved safety and efficacy of medical and surgical methods when used alone or in combination and as adjuncts to osmotic dilators. An important aspect of D&E, cervical preparation, is not a one-size-fits-all practice; the approach and methods are contingent on patient, provider and setting and should consider all the evidence-based options.