Miscarriage risk increases each week alcohol is used in early pregnancy
August 10, 2020
Science Daily/Vanderbilt University Medical Center
Each week a woman consumes alcohol during the first five to 10 weeks of pregnancy is associated with an incremental 8% increase in risk of miscarriage, according to a study by Vanderbilt University Medical Center (VUMC) researchers.
The findings, published in the American Journal of Obstetrics and Gynecology, examine the timing, amount and type of alcohol use during pregnancy and how these factors relate to miscarriage risk before 20 weeks' gestation.
Impact of alcohol use rises through the ninth week of pregnancy, and risk accrues regardless of whether a woman reported having fewer than one drink or more than four drinks each week. Risk is also independent of the type of alcohol consumed and whether the woman had episodes of binge drinking.
Though most women change their alcohol use after a positive pregnancy test, consuming alcohol before recognizing a pregnancy is common among both those with a planned or unintended pregnancy. Half of the 5,353 women included in the analysis reported alcohol use around conception and during the first weeks of pregnancy.
The median gestational age for stopping alcohol use was 29 days. Although 41% of women who changed their use did so within three days of a positive pregnancy test, those who stopped consumption near their missed period had a 37% greater risk of miscarriage compared to women who did not use alcohol.
"Abstaining from alcohol around conception or during pregnancy has long been advised for many reasons, including preventing fetal alcohol syndrome. Nonetheless, modest levels of consumption are often seen as likely to be safe," said Katherine Hartmann, MD, PhD, vice president for Research Integration at VUMC and principal investigator for the Right from the Start cohort, from which participants were enrolled in the study.
"For this reason, our findings are alarming. Levels of use that women, and some care providers, may believe are responsible are harmful, and no amount can be suggested as safe regarding pregnancy loss."
According to the researchers, one in six recognized pregnancies ends in miscarriage, which brings great emotional cost and leaves unanswered questions about why the miscarriage occurred.
Biologically, little is known about how alcohol causes harm during early pregnancy, but it may increase miscarriage risk by modifying hormone patterns, altering the quality of implantation, increasing oxidative stress or impairing key pathways.
Because alcohol use is most common in the first weeks -- when the embryo develops most rapidly and lays down the pattern for organ development -- understanding how timing relates to risk matters.
Risk did not peak in patterns related to alcohol use in specific phases of embryonic development, and there was no evidence that a cumulative "dose" of alcohol contributed to level of risk.
The study recruited women planning a pregnancy or in early pregnancy from eight metropolitan areas in Tennessee, North Carolina and Texas. Participants were interviewed during the first trimester about their alcohol use in a four-month window.
"Combining the facts that the cohort is large, comes from diverse communities, captures data early in pregnancy and applies more advanced analytic techniques than prior studies, we're confident we've raised important concerns," said Alex Sundermann, MD, PhD, the study's first author and recent graduate of the Vanderbilt Medical Scientist Training Program.
To avoid increased risk of miscarriage, the researchers emphasize the importance of using home pregnancy tests, which can reliably detect pregnancy before a missed period, and ceasing alcohol use when planning a pregnancy or when pregnancy is possible.
https://www.sciencedaily.com/releases/2020/08/200810102430.htm
Fathers-to-be should avoid alcohol six months before conception
Parental alcohol consumption linked to raised risk of congenital heart disease
October 3, 2019
Science Daily/European Society of Cardiology
Aspiring parents should both avoid drinking alcohol prior to conception to protect against congenital heart defects, according to research published today in the European Journal of Preventive Cardiology, a journal of the European Society of Cardiology (ESC).
Drinking alcohol three months before pregnancy or during the first trimester was associated with a 44% raised risk of congenital heart disease for fathers and 16% for mothers, compared to not drinking. Binge drinking, defined as five or more drinks per sitting, was related to a 52% higher likelihood of these birth defects for men and 16% for women.
'Binge drinking by would-be parents is a high risk and dangerous behaviour that not only may increase the chance of their baby being born with a heart defect, but also greatly damages their own health,' said study author Dr Jiabi Qin, of Xiangya School of Public Health, Central South University, Changsha, China.
Dr Qin said the results suggest that when couples are trying for a baby, men should not consume alcohol for at least six months before fertilisation while women should stop alcohol one year before and avoid it while pregnant.
Congenital heart diseases are the most common birth defects, with approximately 1.35 million babies affected every year. These conditions can increase the likelihood of cardiovascular disease later life, even after surgical treatment, and are the main cause of perinatal death. Alcohol is a known teratogen and has been connected with fetal alcohol spectrum disorder (FASD). Around one in four children with FASD have congenital heart disease, indicating that alcohol might also be implicated in these disorders.
Previous studies investigating the link between alcohol and congenital heart disease have focused on prospective mothers, with inconclusive results. This is the first meta-analysis to examine the role of paternal alcohol drinking.
The researchers compiled the best data published between 1991 and 2019, which amounted to 55 studies including 41,747 babies with congenital heart disease and 297,587 without. The analysis showed a nonlinear dose-response relationship between parental alcohol drinking and congenital heart diseases.
Dr Qin said: 'We observed a gradually rising risk of congenital heart diseases as parental alcohol consumption increased. The relationship was not statistically significant at the lower quantities.'
Regarding specific defects, the study found that compared to abstinence, maternal drinking was correlated to a 20% greater risk of tetralogy of Fallot, a combination of four abnormalities in the heart's structure.
The authors noted that this was an observational study and does not prove a causal effect, nor does it prove that paternal drinking is more harmful to the fetal heart than maternal drinking. The data cannot be used to define a cut-off of alcohol consumption that might be considered safe.
Dr Qin said: 'The underlying mechanisms connecting parental alcohol and congenital heart diseases are uncertain and warrant further research. Although our analysis has limitations -- for example the type of alcohol was not recorded -- it does indicate that men and women planning a family should give up alcohol.'
https://www.sciencedaily.com/releases/2019/10/191003074846.htm