Vaginal progesterone in women with twin gestations complicated by short cervix: a retrospective cohort study.

OBJECTIVE: To determine whether the use of vaginal progesterone in twin gestations with a cervical length (CL) of ≤2.5 cm is associated with a reduced risk of preterm delivery. DESIGN: Retrospective cohort study. SETTING: Tertiary-care medical centre in New York City. POPULATION: Women with twin gestations undergoing sonographic cervical length screening. METHODS: Women with twin gestations with a CL of ≤2.5 cm between 16 and 32 weeks of gestation, and who delivered at our centre between 2010 and 2013, were included. We evaluated the impact of vaginal progesterone on the risk of preterm delivery using a Cox proportional hazard model, adjusted for potential confounding factors. We then performed a propensity score analysis using inverse probability of treatment weights to account for treatment selection bias and confounding. MAIN OUTCOME MEASURE: Delivery prior to 35 weeks of gestation. RESULTS: Of the 167 twin pregnancies analysed, 61 (35.7%) were treated with vaginal progesterone. The hazard ratio (HR) of delivery prior to 35 weeks of gestation in the vaginal progesterone group, compared with the no vaginal progesterone group, was 1.8 (95% confidence interval, 95% CI 1.5-3.1) in the unadjusted analysis, 1.4 (95% CI 0.7-3.2) following multivariable adjustment for confounding factors, and 1.5 (95% CI 1.1-2.3) using propensity score methods. CONCLUSION: Women with more risk factors for preterm delivery were more likely to be treated with vaginal progesterone. After statistically correcting for this with propensity score methods, we found that vaginal progesterone therapy in twin pregnancies with a CL ≤2.5 cm was associated with an increased risk of preterm delivery.

Effect of cervical cerclage on rate of cervical shortening.

OBJECTIVE: Although cerclage has been shown to reduce the risk of recurrent preterm birth in a high-risk patient population, the mechanism by which this occurs is not well understood. Our objective was to evaluate whether cerclage affects the rate of cervical shortening taking into account exposure to 17-hydroxyprogesterone and vaginal progesterone. METHODS: This was a retrospective cohort study of women who had serial cervical length measurements due to a history of spontaneous preterm delivery. Demographic data, obstetric history, progesterone administration, delivery information and serial cervical length measurements were collected. The rate of cervical shortening was compared in women with and without cerclage. Subgroup analyses were performed to compare rates of cervical shortening by indication for cerclage (history indicated vs ultrasound indicated) and outcome in the current pregnancy (cerclage vs no cerclage among those who delivered preterm). RESULTS: A total of 414 women were included of whom 32.4% (n = 134) had a cerclage. There was no difference in the rate of cervical shortening between the cerclage (0.8 mm/week) and no-cerclage (1.0 mm/week, P = 0.43) groups. The rates of cervical shortening among history-indicated and ultrasound-indicated cerclage groups were similar (0.9 vs 1.3 mm/week, respectively, P = 0.2). Among patients with a preterm delivery in the index pregnancy, the rates of cervical shortening among those with (1.31 mm/week) and without (1.28 mm/week, P = 0.78) cerclage were also similar. CONCLUSION: Cervical shortening among women with cerclage occurs at a similar rate to that among women without a cerclage, regardless of indication for cerclage or pregnancy outcome.

Pregnancy and HIV transmission among HIV-discordant couples in a clinical trial in Kisumu, Kenya.

OBJECTIVES: A large proportion of new HIV infections in sub-Saharan Africa occur in stable HIV-discordant partnerships. In some couples, the strong desire to conceive a child may lead to risky behaviour despite knowledge of discordant serostatus. Our objective was to compare HIV transmission between discordant couples who did and did not conceive during participation in a clinical trial. METHODS: Five hundred and thirty-two HIV-discordant couples were followed for up to 2 years in Kisumu, Kenya as part of the Partners in Prevention HSV/HIV Transmission Study. Quarterly HIV-1 antibody and urine pregnancy test results were analysed. RESULTS: Forty-one HIV-1 seroconversions occurred over 888 person-years of follow-up, resulting in an annual incidence of 4.6/100 person-years. Twenty seroconversions occurred among 186 HIV-1-uninfected individuals in partnerships in which pregnancy occurred (10.8% of HIV-1-negative partners in this group seroconverted), in comparison to 21 seroconversions among 353 uninfected individuals in partnerships in which pregnancy did not occur (5.9% of HIV-1-negative partners seroconverted), resulting in a relative risk of 1.8 [95% confidence interval (CI) 1.01-3.26; P<0.05]. CONCLUSIONS: Pregnancy was associated with an increased risk of HIV seroconversion in discordant couples. These data suggest that the intention to conceive among HIV discordant couples may be contributing to the epidemic.