Latest research: Does spontaneous preterm birth increase risk of CVD?


Contemporary OB/GYN provides information on the latest research on the possibility of a link between cardiovascular disease and spontaneous preterm birth; whether or not contraceptive expiration dates might be conservative; and helping answer the question of whether or not the HPV vaccine causes more sexual activity.

Spontaneous preterm delivery (SPTB) may double a woman’s future risk of developing ischemic heart disease (IHD), stroke, or overall cardiovascular disease (CVD) over time, according to results of a new meta-analysis. While adding to previous such studies that suggest a link between preeclampsia and CVD, the researchers caution that future study is needed to determine how SPTB fits in clinically with traditional CVD risk factors.

The authors, from the Netherlands, analyzed 10 cohort studies with samples sizes ranging from 3,706 to 923,686 and follow-up ranging from 12 to 35 years. All of the studies were performed in northwestern European countries with predominantly white populations. The study dates ranged from 1966 to July 17, 2014 in Medline to 1980 to July 17, 2014 in Embase.

All of the studies in the meta-analysis assessed the relationship between SPTB and fatal or nonfatal IHD, stroke, or overall CVD. IHD, stroke, and CVD were assessed through linkage with national registries. Comparisons included were either of women with SPTB versus women with uncomplicated pregnancies or between women with preterm birth by any cause and those with uncomplicated pregnancies, with adjustment for preeclampsia and fetal growth restriction. At least 10 women with a history of SPTB birth had to be included and fatal or nonfatal IHD, stroke, or overall CVD had to be recorded as outcomes.

Read more: March of Dimes report on US preterm birth rate

Evaluation of the studies was performed using the Newcastle-Ottawa quality assessment scale. Hazard ratios were pooled using a random-effects model. The authors found a two-fold increased risk of IHD (HR 1.38, 95% confidence interval [CI] 1.22-1.57), stroke (HR 1.71, 95% CI 1.53-1.91), and overall CVD over time (HR 2.01, 95% CI 1.52-2.65) in women with SPTB, which was consistent for different outcomes in those with a history of SPTB versus those with term delivery.

The strength of the meta-analysis, the researchers said, was inclusion of only high-quality cohort studies that used record linkage or medical records to assess for CVD. Confounders, however, differed between the studies. Limitations of the meta-analysis noted by the authors were lack of analysis of the influence of smoking during pregnancy, dating of gestational age based on last menstrual period, the high rate of heterogeneity in reported HR for CVD and IHD outcomes among studies, and potential for publication bias.

NEXT: Are IUD and contraceptive implant expiration dates too conservative?


Implants and IUDs: Do expiration dates reflect reality?

The 3- and 5-year labeling for use of the levonogestrel intrauterine devices (IUD) and etonogestrel implant recommended by the US Food and Drug Administration (FDA) may be conservative, according to results of new research.

Researchers from Washington University prospectively assessed the effectiveness of the birth control devices by identifying 237 implant users and 263 levonogestrel IUD users who were willing to continue using the devices past the FDA-approved duration. The unintended pregnancy rate per 100 women-years was calculated. Women with the etonogestrel implants were given the option of periodic venipuncture to analyze serum etonogestrel levels and a Kruskal-Wallis test was used to compare the levels of etonogestrel across body mass index (BMI) groups.

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Overall the implant users were followed up for 229.4 women years. Of the 237 women, 123 used the etonogestrel implant for 4 years and 34 used it for 5 years. No pregnancies were documented, for a failure rate of 0 (one-sided 97.5% confidence interval [CI] 0-1.61) per 100 women-years. The median and range of etonogestrel levels at 3 years was 88.8 pg/mL (range 63.8-802.6 pg/mL) and at 4 years of use it was 177.0 pg/mL (67.9-470.5 pg/mL). Levels of etonogestrel did not differ by BMI at either 3 years (P = .79) or 4 years (P = .47).

The levonogestrel IUD users were followed for 197.7 women-years. There was 1 documented pregnancy, for a failure rate of 0.51 (95% CI 0.01-2.82) per 100 women-years.

Investigators concluded that their preliminary findings indicate that both the etonogestrel implant and levonogestrel IUD appear to be very effective for at least an additional year more than the FDA approved 3 and 5 years, respectively. 

Next: Does the HPV vaccine really lead to more unsafe sexual activity? 


Study challenges perception that HPV vaccination leads to unsafe sex

Despite parental worries, a recent study of more than 21,000 females indicates that vaccination for human papillomavirus (HPV) is not associated with an increase in sexually transmitted infections (STIs).

More: FDA approves Gardasil 9

The information analyzed, on girls aged 12 to 18, was from a large, longitudinal database of individuals who were insured from January 1, 2005 to December 31, 2010 in the United States. One or more medical claims in a given quarter for herpes, gonorrhea, HIV/AIDS, syphilis, or chlamydia constituted a definition of STI.  Difference-in difference analysis was used to compare the changes in STI rates among those who received the HPV vaccine before and after the vaccination (index quarter) to age-matched counterparts who hadn’t received the vaccine.

Overall the rate of STIs was higher the year before vaccination in those girls who received the HPV vaccine (94 of 21,610; 4.3 per 1000) than in the age-matched nonvaccinated cohort (522 of 186,501; 2.8 per 1000) (adjusted odds ratio, 1.37; 95% confidence interval [CI], 1.09-1.71; P = .007). The rate of STIs increased in the year following vaccination for both the nonvaccinated group (781 of 186,501; 4.2 per 1000) and the vaccinated group (147 of 21,610; 6.8 per 1000) (adjusted odds ratio, 1.50; 95% CI, 1.25-1.79; P < .001). Because the difference-in difference odds ratio was 1.05 (95% CI, 0.80-1.38; P = .74), the implication is that the HPV vaccine was not tied to an increase in STIs relative to the growth found in nonvaccinated girls.

The researchers concluded that the HPV vaccine was not linked to an increase in STIs in females, which would suggest that the vaccine does not promote unsafe sex.

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