By: Natalie Sipes, DO
Editor’s Note: Preconception counseling is a vital aspect of women’s health and reproductive planning. The earlier a woman knows she is pregnant, the sooner she can establish healthier practices that may lead to better outcomes. The study by Branum and Ahrens [1] summarized below assessed data regarding self-reported awareness of pregnancy timing. Given the potential implications for both mother and child, the research sought to study trends in this knowledge over time. Natalie Sipes summarized the study while on the FACTS elective in fertility awareness . This award-winning online elective is now also offered to medical residents as FACTS continues to educate current and future medical professionals in fertility awareness-based methods (FABMs) and restorative approaches in women’s health.
Introduction
In recent decades, the rate of documented miscarriages appears to have increased, yet the cause of this trend noted in some studies remains unknown. One possible explanation is that women were finding out they were pregnant earlier, resulting in more miscarriages being detected. Researchers Amy Branum and Katherine Ahrens set out to discover if this was a true reason for the concerning increase in miscarriages that had previously been observed. Their study [1] examined self-reported data from women in the United States across a 23-year span and assessed for a linear change in timing of pregnancy awareness.
“In recent decades, the rate of documented miscarriages appears to have increased … one possible explanation is that women were finding out they were pregnant earlier.”
Methodology
Data on self-reported pregnancy awareness were gathered from the National Survey of Family Growth for women ages 15 to 44 from the years 1995, 2002, 2006-2010, and 2011-2013. For each completed pregnancy within the 4 or 5 years prior to the interview, women responded to the question, “How many weeks pregnant were you when you learned that you were pregnant?” Pregnancies that ended in induced abortion or a live birth put up for adoption were excluded. This resulted in a sample size of 17,406 women.
Maternal characteristics were assessed and the timing of pregnancy awareness was compared in relation to these attributes. These characteristics included age at pregnancy conception, race, level of education, percentage of poverty level, marital status, smoking during pregnancy, intentionality of pregnancy, and total number of pregnancies. All were self-reported within the same survey.
Gestational age at the time of pregnancy awareness was split into “early awareness” (0-6 weeks) or “late awareness” (≥7 weeks). The association of pregnancy awareness of 7 or more weeks with each maternal characteristic was estimated with prevalence ratios using adjusted predicted prevalence estimates. The models controlled for confounding by maternal age, race, and intendedness of pregnancy. Other variables such as smoking during pregnancy, pregnancy outcome, and week of prenatal care initiation were noted as potential consequences of the timing of pregnancy awareness and were not included in this analysis. Linear regression was utilized to look at the trend in timing of pregnancy awareness. Given the natural bias by maternal age in retrospective time trend data, this model was adjusted for maternal age.
Results
The analysis found several characteristics that were associated with late pregnancy awareness. Overall, the mean gestational age of pregnancy awareness was 5.5 weeks with a standard deviation of 0.04. The overall prevalence of late pregnancy awareness was 23%. Only in 2002 was the time of pregnancy awareness significantly lower than in other years.
The study found that in all years studied, younger age correlated with increased late pregnancy awareness. Compared to women aged 25 to 29, younger women were more likely (age 15-19 PR=1.31, age 20-24 PR=1.11) and older women were less likely (age 30-34 PR=0.82, age 35-44 PR=0.78) to find out about their pregnancies at 7 or more weeks gestation.
“The study found that in all years studied, younger age correlated with increased late pregnancy awareness.”
In the years 1995, 2006-2010, and 2011-2013, Hispanic women were significantly more likely to find out about their pregnancies late as compared to non-Hispanic White women. In the years 1995 and 2006-2010 only, non-Hispanic Black women’s pregnancy timing awareness was significantly later than non-Hispanic White women. Lastly, women with intended pregnancies had more early awareness than those with unwanted or mistimed pregnancies.
The linear regression for overall gestational age at time of pregnancy awareness did not show a significant linear trend before or after adjusting for maternal age. This suggests there was not a significant change in timing of pregnancy awareness between the years 1995 and 2013.
Discussion
Strengths and opportunities
This study handled an extensive amount of data spanning over many years. The sample size of over 17,000 women was impressive, adding to the credibility of their findings. The patient characteristics used to draw conclusions were adequately controlled throughout their studies as long as they were not the independent variable in that given analysis. The massive accumulation of data and strategic analysis was a strength of this work.
The most pressing concern with this study was the likelihood of recall bias. The study asked women about their time of pregnancy awareness for the previous 4 to 5 years; some could be expected to remember the exact week they discovered their pregnancy for an event occurring several years earlier. This would be difficult to remember, particularly for women who were not tracking their cycles , which likely comprised most of the population surveyed. Although it would be challenging to assess the accuracy of survey responses, the question was phrased in the same way throughout the surveys. Thus, if a linear change was occurring in timing of pregnancy awareness, it is likely the data would have shown it.
Value of charting the female cycle
This study exemplified the value and applicability of tracking one’s cycles. While the average time for pregnancy awareness was fairly early at 5.5 weeks, this still leaves 5 weeks of fetal growth in which the mother’s behavior could inadvertently affect development. Women with intended pregnancies were aware of their pregnancy earlier, likely because they were more aware of their cycles and changes within their bodies. If more women would track their cycles with mucus analysis, basal body temperature, or even just sensation, the average time of pregnancy awareness would be lower, adding time for healthier choices for both mother and baby.
“Women with intended pregnancies were aware of their pregnancy earlier, likely because they were more aware of their cycles and changes within their bodies.”
Potential Impact of FABMs in Pregnancy Outcomes
It is interesting to consider external factors that could have impacted the data, such as the accessibility or improved reliability of home pregnancy tests. In fact, this data shows these factors did not decrease the time of pregnancy awareness over the last several decades. As home pregnancy tests became available in the 1970s, it is possible there was a shift in timing of awareness at that time that would not have been shown in this study.
An important takeaway from a fertility awareness perspective is the large window of time that remains before women realize they conceived. During this time, many women may not be supplementing folic acid and may be drinking alcohol or smoking even if they would not choose to do so during pregnancy. Given that the early weeks of pregnancy are so crucial for fetal development, even slight changes in the timing of pregnancy awareness can have large effects. Tracking one’s cycles with a fertility awareness-based method (FABM) could signal pregnancy sooner and help women take actions that could prevent adverse outcomes.
More analysis still needs to occur to find the root causes of increasing rates of miscarriage. For couples who have experienced pregnancy loss, cycle tracking is an additional tool on their journey that can help diagnose and treat common conditions that may lead to miscarriage.
References
[1] Branum AM, Ahrens KA. Trends in Timing of Pregnancy Awareness Among US Women. Maternal and Child Health Journal. 2017;21(4):715-726. doi:10.1007/s10995-016-2155-1
ABOUT THE AUTHOR
Natalie Sipes, DO
Natalie Sipes, DO is a first-year resident at KU-Wichita and a graduate of Kansas City University College of Osteopathic Medicine in Kansas City, Missouri. She completed her undergraduate education at Ball State University in Muncie, Indiana. She is pursuing residency in obstetrics and gynecology and is interested in health equity and patient education. Dr. Sipes is excited to play a role in ensuring her patients feel empowered over their bodies and healthcare decisions. She enrolled in the FACTS elective to gain a better understanding of natural family planning methods and ways to share these methods with future patients so they have adequate knowledge to make the reproductive decisions they feel will fit best in their lives.
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