IS THERE AN INCREMENTAL RISE IN THE RISK OF OBSTETRIC INTERVENTION WITH INCREASING MATERNAL AGE

Objective To determine whether increasing maternal age increases the r isk of operative delivery and to investigate whether such a trend is d ue to fetal or maternal factors. Design Analysis of prospectively coll ected data on a maternity unit database. Setting A postgraduate teachi ng hospital. Population 6410 nulliparous women with singleton cephalic pregnancies delivering at term (37-42 weeks of gestation) between 1 J anuary 92 and 31 December 95.Main outcome measures Mode of delivery, r ates of prelabour caesarean section, induction of labour and epidural usage. Results There was a positive, highly significant association be tween increasing maternal age and obstetric intervention. Prelabour (P < 0.001) and emergency (P < 0.001) caesarean section, instrumental va ginal delivery (spontaneous labour P < 0.001; induced labour P = 0.001 ), induction of labour (P < 0.001) and epidural usage in spontaneous l abour (P = 0.005) all increased with increasing age. In the second sta ge of labour fetal distress and failure to advance, requiring instrume ntal delivery, were both more likely with increasing maternal age (in both P < 0.001). Epidural usage in induced labour and the incidence of small for gestational age newborns did not increase with increasing m aternal age (P = 0.68 and P = 0.50, respectively). Conclusions This st udy demonstrates that increasing maternal age is associated with an in cremental increase in obstetric intervention. Previous studies have de monstrated a significant effect in women older than 35 years of age, b ut these data show changes on a continuum from teenage years. This fin ding may reflect a progressive, age-related deterioration in myometria l function.