Smoking before getting pregnant could still hurt your baby

By Tom Campbell via SWNS

Moms-to-be who quit smoking when they become pregnant could still cause damage to their child, scientists warned.

Smoking in the weeks before falling pregnant could still be delaying the development of their child.

Babies in the womb were nearly a day behind in women who smoked 10 or more cigarettes a day, researchers found.

Smoking before and after pregnancy also led to smaller fetuses at 20 weeks and smaller babies at birth.

An estimated 13.5 percent of adults living in the UK smoke cigarettes, which contribute to 78,000 deaths a year, experts said.

Now scientists warned women looking to get pregnant should put down the pack well before conceiving.

Dr. Melek Rousian, one of the authors of the new 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 a lower birth weight.

"Part of fetal and neonatal outcomes can be explained by smoking during the periconceptional period and the delay in embryonic development.”

The researchers followed 689 pregnant women starting 14 weeks before conception and finishing 10 weeks after, which is known as the periconceptional period.

These women were taking part in a large prospective study at the Erasmus MC, University Medical Center in Rotterdam between 2010 and 2018.

After ten weeks, they found the embryo's development was delayed by nearly 24-hours if women smoked ten or more cigarettes a day.

This delay increased to 1.6 days among those who had conceived by means of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

Embryos were not able to “catch up” their development over the course of the pregnancy, the researchers also found.

They were also more likely to be born small, with an average birth weight 93 grams lower than babies born to non-smokers.

Dr. Rousian added: "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.

"We think that perhaps there is some catch-up growth during the second and third trimesters, but the delay in morphological development cannot be fully recuperated during the course of the pregnancy, as is shown by the 20-week ultrasound scans and birth weights.”

Although mothers taking part in the study did not represent the general population, the results could be important for all women planning to become pregnant.

Dr. Rousian said: "The results of this study emphasize the importance of smoking cessation prior to conception and that efforts to help women stop smoking should focus on this time window.

"If possible, women should stop smoking from the very moment they plan to become pregnant, but it’s always a good thing to stop smoking anyway, particularly at any stage of pregnancy.

"Smoking not only impacts an embryo’s growth during pregnancy and birth weight, but also embryo development right from the very early stages of pregnancy."

The researchers are now exploring different ways of helping future parents stop smoking through face-to-face consultations, follow-up visits and digital interventions.

Dr Rousian added: "This is why the periconceptional period is an important area of research because many future parents are not aware of the presence of a developing embryo in the early days when a pregnancy has not yet been confirmed."

How a baby develops can be studied in much greater detail thanks to better imaging techniques like virtual reality (VR).

Dr Carsten Pietersma, the first study author, said: "Since it is known that smoking negatively affects foetal growth during pregnancy, we wanted to study how this may also impact the development of the embryo.

"This developmental morphological study using the Carnegie stages takes multiple dimensions of the embryo into account, instead of just one growth parameter.”

The findings were published in the journal Human Reproduction.