Nicotine patch & gum linked to birth defects

John (Gold)
John (Gold)

January 4th, 2006, 8:47 am #1

Mothers told of nicotine
patch link to birth defects
by JULIE WHELDON, Daily Mail
07:41am 3rd January 2006
Using nicotine patches and gum in early pregnancy makes birth defects more likely, research suggests.
The babies of women who use nicotine replacement therapy in the first 12 weeks of pregnancy have a 60 per cent higher chance of birth defects than non-smokers, scientists said.
Their findings come days after UK experts said pregnant women should no longer be warned against using nicotine replacement therapies.
The Medicines and Healthcare products Regulatory Agency said the risks of smoking for pregnant women outweigh the medicines' potential side effects - and restrictions on packets of patches and other therapies should be removed.
The latest study, reported in the journal Obstetrics And Gynaecology, was based on almost 77,000 pregnant women from Denmark.
All were asked about smoking habits and use of nicotine replacement therapies during the first 12 weeks of pregnancy.
There were 20,603 births among smoking mothers and 56,165 among non-smokers. Among the non-smokers were 250 ex-smokers using nicotine substitutes.
Some previous research has shown that smoking raises the risk of birth defects such as cleft palates, heart problems and digestive disorders.
But the study found that smokers did not have a higher rate of birth defects than non-smokers, with about 5 per cent of babies in both groups having some kind of congenital deformity. This may be because smoking raises the risk of miscarriage, meaning more babies may die in the womb rather than be born with defects.
However, there was a greater risk of birth defects among those on nicotine replacement therapies, compared to the other non-smokers.
60 per cent greater risk
Those using the therapies had a 60 per cent greater risk of birth defects than non-smokers - and double the chance of musculoskeletal malformations such as hip problems.
Among the 250 non-smokers using nicotine replacement, 19 were born with birth defects - 7.6 per cent.
The researchers, led by Maria Morales-Suarez-Varela of the University of Valencia, in Spain, stressed their findings are based on small numbers.
But they said it is vital that smokers planning a pregnancy are helped to give up, as smoking can cause low birth weights and more premature births.
And they called for more research into the potential impact of nicotine substitutes on a developing foetus.
It appears the safest option for expectant mothers is to give up nicotine altogether.
Tobacco smoke is the greatest toxin to which babies are exposed in the womb and women wanting to become pregnant should be offered help in quitting, the scientists said.
"But whether these smoking cessation programs should include nicotine is unknown," they said.
"Nicotine is fetotoxic, but one could argue that if nicotine replacement (patches, gum or inhalers) is the only effective smoking cessation tool, for some pregnant women it is a better alternative than smoking because hundreds of potentially harmful substances are replaced by a single one.
"On the other hand nicotine substitutes have a different absorption route and may reach higher peak values.
"The potential role of nicotine substitutes in causing musculoskeletal, congenital malformations must be more carefully studied, especially for smokers who are considering pregnancy."
The study did not state which therapies were used but it is thought they were comparable to types available in Britain.
Packs of the therapies sold in the UK previously advised against use by the under-18s, pregnant women and those with heart, kidney and liver conditions.
But last week the Government said it would remove the restrictions following experts' advice.
Yesterday the MHRA said its advisers had considered all the available evidence when it made its recommendations on extending use of the therapies to pregnant women.
But it would consider any research that emerged for a licensed medicine.
©2006 Associated Newspapers Ltd


Smoking Habits, Nicotine Use, and Congenital Malformations
Obstetrics & Gynecology January 1, 2006;107:51-57
© 2006 by The American College of Obstetricians and Gynecologists


María M. Morales-Suárez-Varela, MD, PhD1,2, Camilla Bille3, Kaare Christensen3 and Jorn Olsen, MD, PhD4,5

From the 1Unit of Public Health and Environmental Care, Department of Preventive Medicine, University of Valencia, Valencia, Spain; 2Unit of Clinical Epidemiology, Dr. Peset University Hospital, Valencia, Spain; 3Institute of Public Health, Epidemiology, University of Southern Denmark, Odense, Denmark; 4Danish Epidemiology Science Centre, University of Aarhus, Aarhus, Denmark; and 5Department of Epidemiology, School of Public Health, University of California Los Angeles, Los Angeles, California.

OBJECTIVE: We examined whether maternal smoking and use of nicotine substitutes during the first 12 weeks of pregnancy increased the prevalence of congenital malformations in general and of certain congenital malformations in particular.

METHODS: In the Danish National Birth Cohort (1997-2003) we identified 76,768 pregnancies (and their subsequent singleton births); 20,603 were exposed to tobacco smoking during the first 12 weeks of pregnancy. Birth outcomes were collected by linkage to the Central Population Register, the National Patients Register, and the National Birth Register. We identified congenital malformations from the Hospital Medical Birth Registry as they were recorded at birth or in the first year of follow-up.

RESULTS: Smoking mothers were younger, weighed less, consumed more alcohol, and had received less education. Children exposed to prenatal tobacco smoking had no increase in congenital malformations prevalence compared with the nonexposed children in both crude and adjusted analyses. Children born to nonsmokers, but who used nicotine substitutes, had a slightly increased relative congenital malformations prevalence ratio; relative prevalence rate ratio was 1.61 (95% confidence interval 1.01-2.58), which represents a 60% increased risk. When the analysis was restricted to musculoskeletal malformations, the relative prevalence rate ratio was 2.63 (95% confidence interval 1.53-4.52).

CONCLUSION: Our results showed no increase in congenital malformations related to prenatal tobacco smoking. However, we identified an increase of malformations risk in nonsmokers using nicotine substitutes. This finding needs to be replicated in other data sources.

LEVEL OF EVIDENCE: II-2
Copyright © 2006 by the American College of Obstetricians and Gynecologists.[/size]
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