Effects of Smoking Specified as Cigarettes per Day and Maternal Body Mass Index on Hypertensive Disorders of Pregnancy

Abstract

Background:

We have previously described the prevalence in pregnancy of hypertension, proteinuria, oedema and preeclampsia/eclampsia according to maternal body mass index (BMI) and smoking status. We found that these disorders were less frequent among smoking women. To investigate whether this relationship is causal or a chance finding, we here present an analysis according to BMI and smoking specified according to the number of cigarettes consumed per day.

Materials and Methods:

Data were from the German Perinatal Survey of 1998–2000. We classified women by BMI as underweight (BMI<18.5 kg/m²), normal weight (BMI 18.5–24.99 kg/m²), overweight (25.0–29.99 kg/m²), or obese (BMI≥30 kg/m²). Smoking was categorised as being a non-smoker or smoking 1–7, 8–14 or ≥ 15 cigarettes per day. Datasets from 433 669 singleton pregnancies with information on maternal BMI and smoking were included in the analysis.

Results:

In all BMI categories hypertension, moderate to severe oedema, and preeclampsia/eclampsia became less prevalent with increasing maternal cigarette consumption. Dose-dependence was not convincing for proteinuria.

Conclusions:

Dose-dependence in the relationship between smoking and hypertensive disorders of pregnancy argues against a chance finding and for a causal relationship.

Zusammenfassung

Hintergrund und Fragestellung:

Die Prävalenz in der Schwangerschaft von Hypertonie, Proteinurie, Ödemen und Gestose/Eklampsie in Abhängigkeit vom maternalen Body-Mass-Index (BMI) und Raucherstatus wurde zuvor von uns untersucht. Es zeigte sich, dass diese Gesundheitsstörungen bei Raucherinnen weniger häufig auftraten. Um zu untersuchen, ob es sich dabei um eine ursächliche Beziehung oder einen Zufallsbefund handelt, wird hier eine Analyse hinsichtlich des BMI und des Rauchens spezifiziert nach der Anzahl der pro Tag konsumierten Zigaretten präsentiert.

Material und Methodik:

Die Daten entstammen der deutschen Perinatalerhebung von 1998–2000. Frauen wurden nach dem BMI als untergewichtig (BMI < 18,5 kg/m²), normalgewichtig (BMI 18,5–24,99 kg/m²), übergewichtig (25,0–29,99 kg/m²) oder adipös (BMI ≥ 30 kg/m²) klassifiziert und nach dem Rauchverhalten als Nichtraucherinnen oder Raucherinnen von 1–7, 8–14 oder ≥15 Zigaretten pro Tag kategorisiert. Datensätze von 433 669 Einlingsschwangerschaften mit Angaben zu maternalem BMI und Rauchverhalten konnten in die Analyse eingeschlossen werden.

Ergebnisse:

In allen BMI-Kategorien wurden Hypertonie, Ödeme und Gestose/Eklampsie mit zunehmendem Zigarettenkonsum seltener. Für Proteinurie ergab sich keine überzeugende Dosis­abhängigkeit.

Schlussfolgerung:

Die Dosisabhängigkeit in der Beziehung zwischen Rauchen und hypertensiven Schwangerschaftserkrankungen spricht gegen einen Zufallsbefund und für eine ursächliche Beziehung.

Key words

smoking - hypertensive disorders - pregnancy

Schlüsselwörter

Rauchen - hypertensive Erkrankungen - Schwangerschaft

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