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Impact of preconception enrollment on birth enrollment and timing of exposure assessment in the initial vanguard cohort of the U.S. National Children's Study.

Stanford JB, Brenner R, Fetterer D, Palmer L, Schoendorf KC, U.S. National Children’s Stu - BMC Med Res Methodol (2015)

Bottom Line: Among women who gave birth, and who had enrolled preconception trying for pregnancy, 67.3% were white non-Hispanic, compared to 50.0% of preconception women not trying for pregnancy, and 61.5% of pregnant women.Women enrolled preconception who were trying for pregnancy had higher cumulative probability of pregnancy at one year compared to women not trying (adjusted 86% versus 56%).Time to pregnancy was shorter for women actively trying for pregnancy.

View Article: PubMed Central - PubMed

Affiliation: Department of Family and Preventive Medicine, University of Utah, 375 Chipeta Way, Salt Lake City, UT, 84108, USA. joseph.stanford@utah.edu.

ABSTRACT

Background: The initial vanguard cohort of the U.S. National Children's Study was a pregnancy and birth cohort study that sought to enroll some women prior to pregnancy, and to assess exposures early in pregnancy.

Methods: During the recruitment phase (2009-2010), geographically based sampling was used to recruit women early in pregnancy and women not currently pregnant, not using contraception and heterosexually active. We assessed the following outcomes for women enrolled preconception and early in pregnancy: yield of births; demographic characteristics of births for different enrollment groups; time to pregnancy for preconception women; and the timing of study visits for exposure assessment.

Results: 1399 women were recruited into the initial vanguard cohort: 429 preconception (198 trying for pregnancy, and 231 not trying) and 970 already pregnant. There were 1135 pregnancies (81% of women) and 922 newborns enrolled (81% of pregnancies) through September 2012. Preconception women represented 30.6% of women enrolled, and contributed 14.5% of births. Among women who gave birth, and who had enrolled preconception trying for pregnancy, 67.3% were white non-Hispanic, compared to 50.0% of preconception women not trying for pregnancy, and 61.5% of pregnant women. Women enrolled preconception who were trying for pregnancy had higher cumulative probability of pregnancy at one year compared to women not trying (adjusted 86% versus 56%). Of 165 women enrolled preconception who became pregnant, 19% had a study visit within 30 days of conception. By 10.5 weeks after conception, 75% of women enrolled preconception had completed a pregnancy study visit; for women enrolled pregnant, the 75% threshold was reached at 28.4 weeks.

Conclusions: There were demographic differences in births from women enrolled preconception trying for pregnancy, preconception not trying for pregnancy, or during pregnancy. Time to pregnancy was shorter for women actively trying for pregnancy. Most women enrolled preconception did not have exposure assessment within 30 days of conception, but they did have exposure assessment much earlier during pregnancy than women who enrolled during pregnancy.

No MeSH data available.


Related in: MedlinePlus

Time from screening to conception by pregnancy probability group (High Tryer versus High Non-Tryer) at initial screening, adjusted for loss to follow-up. Shading represents 95 % confidence interval
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Fig2: Time from screening to conception by pregnancy probability group (High Tryer versus High Non-Tryer) at initial screening, adjusted for loss to follow-up. Shading represents 95 % confidence interval

Mentions: We assessed time to pregnancy for all the women identified as preconception eligible at screening. (Many of these women did not actually enroll preconception, but rather enrolled when they were already pregnant, because their screening happened prior to the implementation of the preconception part of the study in January 2010.) Of the 1399 women who ultimately enrolled, 403 women were identified at the time of initial screening as eligible for preconception enrollment (215 high non-tryers, and 188 tryers). Of these women, 16 high non-tryers and 23 high tryers subsequently had an estimated date of conception determined that was on or prior to the date of screening (i.e., they were actually pregnant at screening although not identified as such), and these are excluded from the following analysis, as are the 4 women for whom an estimated date of conception was not recorded. The crude probability of conception at 365 days was 45 % (+/− standard deviation 3.5 %) for high non-tryers and 76 % (+/− 3.5 %) for high tryers. The probability of conception adjusted for loss to follow-up, shown in Fig. 2, was about 56 % (+/− 4.0 %) for high non-tryers and 86 % (+/− 2.9 %) for high tryers at one year, respectively. The difference in cumulative probability of conception was significantly different between the groups (p < 0.001, log rank test).Fig. 2


Impact of preconception enrollment on birth enrollment and timing of exposure assessment in the initial vanguard cohort of the U.S. National Children's Study.

Stanford JB, Brenner R, Fetterer D, Palmer L, Schoendorf KC, U.S. National Children’s Stu - BMC Med Res Methodol (2015)

Time from screening to conception by pregnancy probability group (High Tryer versus High Non-Tryer) at initial screening, adjusted for loss to follow-up. Shading represents 95 % confidence interval
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4581516&req=5

Fig2: Time from screening to conception by pregnancy probability group (High Tryer versus High Non-Tryer) at initial screening, adjusted for loss to follow-up. Shading represents 95 % confidence interval
Mentions: We assessed time to pregnancy for all the women identified as preconception eligible at screening. (Many of these women did not actually enroll preconception, but rather enrolled when they were already pregnant, because their screening happened prior to the implementation of the preconception part of the study in January 2010.) Of the 1399 women who ultimately enrolled, 403 women were identified at the time of initial screening as eligible for preconception enrollment (215 high non-tryers, and 188 tryers). Of these women, 16 high non-tryers and 23 high tryers subsequently had an estimated date of conception determined that was on or prior to the date of screening (i.e., they were actually pregnant at screening although not identified as such), and these are excluded from the following analysis, as are the 4 women for whom an estimated date of conception was not recorded. The crude probability of conception at 365 days was 45 % (+/− standard deviation 3.5 %) for high non-tryers and 76 % (+/− 3.5 %) for high tryers. The probability of conception adjusted for loss to follow-up, shown in Fig. 2, was about 56 % (+/− 4.0 %) for high non-tryers and 86 % (+/− 2.9 %) for high tryers at one year, respectively. The difference in cumulative probability of conception was significantly different between the groups (p < 0.001, log rank test).Fig. 2

Bottom Line: Among women who gave birth, and who had enrolled preconception trying for pregnancy, 67.3% were white non-Hispanic, compared to 50.0% of preconception women not trying for pregnancy, and 61.5% of pregnant women.Women enrolled preconception who were trying for pregnancy had higher cumulative probability of pregnancy at one year compared to women not trying (adjusted 86% versus 56%).Time to pregnancy was shorter for women actively trying for pregnancy.

View Article: PubMed Central - PubMed

Affiliation: Department of Family and Preventive Medicine, University of Utah, 375 Chipeta Way, Salt Lake City, UT, 84108, USA. joseph.stanford@utah.edu.

ABSTRACT

Background: The initial vanguard cohort of the U.S. National Children's Study was a pregnancy and birth cohort study that sought to enroll some women prior to pregnancy, and to assess exposures early in pregnancy.

Methods: During the recruitment phase (2009-2010), geographically based sampling was used to recruit women early in pregnancy and women not currently pregnant, not using contraception and heterosexually active. We assessed the following outcomes for women enrolled preconception and early in pregnancy: yield of births; demographic characteristics of births for different enrollment groups; time to pregnancy for preconception women; and the timing of study visits for exposure assessment.

Results: 1399 women were recruited into the initial vanguard cohort: 429 preconception (198 trying for pregnancy, and 231 not trying) and 970 already pregnant. There were 1135 pregnancies (81% of women) and 922 newborns enrolled (81% of pregnancies) through September 2012. Preconception women represented 30.6% of women enrolled, and contributed 14.5% of births. Among women who gave birth, and who had enrolled preconception trying for pregnancy, 67.3% were white non-Hispanic, compared to 50.0% of preconception women not trying for pregnancy, and 61.5% of pregnant women. Women enrolled preconception who were trying for pregnancy had higher cumulative probability of pregnancy at one year compared to women not trying (adjusted 86% versus 56%). Of 165 women enrolled preconception who became pregnant, 19% had a study visit within 30 days of conception. By 10.5 weeks after conception, 75% of women enrolled preconception had completed a pregnancy study visit; for women enrolled pregnant, the 75% threshold was reached at 28.4 weeks.

Conclusions: There were demographic differences in births from women enrolled preconception trying for pregnancy, preconception not trying for pregnancy, or during pregnancy. Time to pregnancy was shorter for women actively trying for pregnancy. Most women enrolled preconception did not have exposure assessment within 30 days of conception, but they did have exposure assessment much earlier during pregnancy than women who enrolled during pregnancy.

No MeSH data available.


Related in: MedlinePlus