Delayed embryonic development at the 20-week ultrasound scan has been found among women who smoke in the 14 weeks before and ten weeks after conception.
Embryonic development is the earliest part of pregnancy and involves intricate coordination of molecular, cellular, and tissue-level processes that must occur according to strict schedules in the first trimester, which takes place during the first three months of pregnancy. For the first time, a team of researchers has found embryo development was delayed by 0.9 days when measured at ten weeks in pregnant women who smoked ten or more cigarettes a day compared to non-smokers. In addition, a delay of 1.6 days was observed in smokers who had conceived through IVF and intracytoplasmic sperm injection (ICSI).
Dr Melek Rousian, a gynaecologist at the University Medical Centre, Rotterdam in the Netherlands, who led the study said: 'One of the key messages of this study is that the delay in embryonic development due to mothers smoking in the periconceptional period is also associated with smaller fetal measurements at the 20-week ultrasound scan and lower birth weight. Part of fetal and neonatal outcomes can be explained by smoking during the periconceptional period and the delay in embryonic development.'
Previous studies investigating the detrimental effects of smoking on prenatal growth and smoking are plentiful, and mostly assumed vasoconstriction of the placenta was behind this. However, it remained unclear which stage of gestation that embryonic morphology and fetal development were affected by smoking.
This study compared measurements taken from seven- to ten-week scans, 20-week scans and birth weight in a group of 689 women, 96 of them smokers, between 2010 and 2018. Analysis showed a 0.9 day delay in fetal development at ten weeks, and smaller femur length at the 20-week scan among women who smoked over ten cigarettes a day compared to non-smokers. Smoking around conception was also associated with a birthweight that was an average of 228g lower in male babies, and 2018g lower in female babies than for non-smokers.
'The impact of periconceptional maternal smoking on delaying embryonic development appears to have a greater effect in the second trimester of pregnancy than at birth,' said Dr Rousian. 'We were able to show a dose-response effect of maternal smoking on embryonic morphology and fetal growth; the more cigarettes a woman smoked, the greater the developmental delay. This stresses the importance of public health initiatives to promote preconception education and care, including effective programmes to assist couples to stop smoking.'
The greater effect of smoking around conception on people who used IVF or ICSI to conceive on the delayed development of their embryos was potentially due to more precise dating of conception or could be due to an actual greater effect, authors concluded.
Sources and References
-
Smoking before and after conception is linked to delayed embryonic development
-
The impact of maternal smoking on embryonic morphological development: the Rotterdam Periconception Cohort
-
Smoking around time of conception may affect growth of embryo
-
Smoking during conception is linked to delayed embryonic development
-
Smoking around time of conception may harm embryo
-
Damage done' smokers who quit when they get pregnant can still harm their child, study shows
Leave a Reply
You must be logged in to post a comment.