Explaining the association of maternal age with Cesarean delivery for nulliparous and parous women

The Effect of Maternal Age on Obstetric Interventions in a Low-Risk Population

INTRODUCTION

Obstetric interventions appear to increase with advancing maternal age, but limited supporting evidence exists, particularly for young women and specifically for prelabor and intrapartum cesarean birth. The aim of this study was to explore the association between obstetric interventions and maternal age in a low-risk population.

METHODS

The study was restricted to all low-risk, nulliparous women with singleton, vertex, term births who gave birth in Iceland from 1997 to 2015, identified in the Icelandic Medical Birth Registry. Logistic regression models were used to calculate adjusted odds ratios (aORs) and 95% CIs for the risks of labor induction, instrumental birth, and cesarean birth (prelabor and intrapartum), according to maternal age group. All models were adjusted for gestational age, year of birth, and demographic factors, and the models for intrapartum cesarean birth were also adjusted for dystocia and fetal distress.

RESULTS

For women aged more than 40 years, the aOR for induction of labor was 4.69 (95% CI, 3.2-6.8) compared with women aged between 25 and 29 years. In women aged more than 40 years, the increased risks for prelabor cesarean birth and intrapartum cesarean birth were 7.4 (95% CI, 3.0-18.0) and 3.6 (95% CI, 2.1-6.0), respectively. The risk of instrumental birth was slightly increased for women aged between 35 and 39 years (aOR, 1.6; 95% CI, 1.3-2.0), compared with women aged between 25 and 29 years, but not for women aged at least 40 years (aOR, 1.1; 95% CI, 0.7-1.9). For women aged less than 20 years, the risk of induction of labor (aOR, 0.8; 95% CI, 0.7-0.9) and instrumental births (aOR, 0.6; 95% CI, 0.5-0.7) was reduced compared with women aged between 25 and 29 years.

DISCUSSION

The risk of interventions generally increased with increasing maternal age, but the risk of instrumental births was not increased for women aged over 40 years. Also, young women were at a decreased risk of induction of labor and instrumental births.

Is ultrasound measured fetal biometry predictive of intrapartum caesarean section for failure to progress?

BACKGROUND

There are global concerns regarding excessive caesarean rates, which could be reduced by identification of risk factors leading to preventative measures such as induction of labour.

AIMS

This study aims to describe the association between antenatal ultrasound and emergency caesarean section for: (i) failure to progress; (ii) other indications; and (iii) any indication.

MATERIALS AND METHODS

Women who had an ultrasound in pregnancy between 36^(+0/7) to 38^(+6/7) weeks at Royal Prince Alfred Hospital from January 2005 to June 2009 were included. Ultrasound parameters were linked to clinical parameters from the maternity database. Missing clinical data were imputed and multiple logistic regression performed.

RESULTS

Fetal biometry data were available for 2006 pregnancies. After adjusting for maternal age, height, body mass index, parity, previous caesarean section and diabetes, caesarean section for failure to progress was associated with estimated fetal weight (odds ratio (OR) 2.24 (95% CI: 1.76-2.84) per 500 g increase); or biparietal diameter (OR 1.51 (1.16-1.97) per 5 mm increase) and abdominal circumference (OR for the 4th quartile (>75th centile) compared with the 10-25th centile group was 2.09 (1.13-3.85)).* There were also non-linear associations between components of fetal biometry and caesarean section for fetal distress and for any indication.

CONCLUSIONS

Components of fetal biometry in the third trimester are associated with intrapartum caesarean section for failure to progress. These parameters could be incorporated into models to predict emergency caesarean section which could lead to implementation of preventative strategies. *[Corrections added on 29 January 2018, after first online publication, '(OR for the 4th quartile (>7th centile)' has been changed to '(OR for the 4th quartile (>75th centile)'.].

Risk of Adverse Obstetric and Neonatal Outcomes by Maternal Age: Quantifying Individual and Population Level Risk Using Routine UK Maternity Data

OBJECTIVE

The objective of this study was to investigate whether moderately increased maternal age is associated with obstetric and neonatal outcome in a contemporary population, and to consider the possible role of co-morbidities in explaining any increased risk.

STUDY DESIGN

Secondary analysis of routinely collected data from a large maternity unit in London, UK. Data were available on 51,225 singleton deliveries (≥22 weeks) occurring to women aged ≥20 between 2004 and 2012. Modified Poisson regression was used to estimate risk ratios for the association between maternal age and obstetric and neonatal outcome (delivery type, postpartum haemorrhage, stillbirth, low birthweight, preterm birth, small for gestational age, neonatal unit admission), using the reference group 20-24 years. Population attributable fractions were calculated to quantify the population impact.

RESULTS

We found an association between increasing maternal age and major postpartum haemorrhage (≥1000ml blood loss) (RR 1.36 95% CI 1.18-1.57 for age 25-29 rising to 2.41 95% CI 2.02-2.88 for age ≥40). Similar trends were observed for caesarean delivery, most notably for elective caesareans (RR 1.64 95% CI 1.36-1.96 for age 25-29 rising to 4.94 95% CI 4.09-5.96 for age ≥40). There was evidence that parity modified this association, with a higher prevalence of elective caesarean delivery in older nulliparous women. Women aged ≥35 were at increased risk of low birthweight and preterm birth. We found no evidence that the risk of stillbirth, small for gestational age, or neonatal unit admission differed by maternal age.

CONCLUSIONS

Our results suggest a gradual increase in the risk of caesarean delivery and postpartum haemorrhage from age 25, persisting after taking into account maternal BMI, hypertension and diabetes. The risk of low birthweight and preterm birth was elevated in women over 35. Further research is needed to understand the reasons behind the high prevalence of elective caesarean delivery in nulliparous older mothers.

Predictors of Unplanned Cesareans among Low-Risk Migrant Women from Low- and Middle-Income Countries Living in Montreal, Canada

BACKGROUND

Research has yielded little understanding of factors associated with high cesarean rates among migrant women (i.e., women born abroad). The objective of this study was to identify medical, migration, social, and health service predictors of unplanned cesareans among low-risk migrant women from low- and middle-income countries (LMICs).

METHODS

We used a case-control research design. The sampling frame included migrant women from LMICs living in Canada less than 8 years, who gave birth at one of three Montreal hospitals between March 2014 and January 2015. Data were collected from medical records and by interview-administration of the Migrant-Friendly Maternity Care Questionnaire. We performed multi-variable logistic regression for low-risk women (i.e., vertex, singleton, term pregnancies) who delivered vaginally (1,615 controls) and by unplanned cesarean indicated by failure to progress, fetal distress, or cephalopelvic disproportion (233 cases).

RESULTS

Predictors of unplanned cesarean included being from sub-Saharan Africa/Caribbean (OR 2.37 [95% CI 1.02-5.51]) and admission for delivery during early labor (OR 5.43 [95% CI 3.17-9.29]). Among women living in Canada less than 2 years predictors were having a humanitarian migration classification (OR 4.24 [95% CI 1.16-15.46]) and admission for delivery during early labor (OR 7.68 [95% CI 3.12-18.88]).

CONCLUSION

Migrant women from sub-Saharan Africa/Caribbean and recently arrived migrant women with a humanitarian classification are at greater risk for unplanned cesareans compared with other low-risk migrant women from LMICs after controlling for medical factors. Strategies to prevent cesareans should consider the circumstances of migrant women that may be contributing to the use of unplanned cesareans in this population.

Maternal age and emergency operative deliveries at term: a population-based registry study among low-risk primiparous women

OBJECTIVE

To study the association between maternal age and emergency operative delivery. The roles of in-labour indications, and birthweight ≥ 4000 g, gestational age ≥ 42 weeks, induction of labour, and epidural use, according to maternal age were explored.

DESIGN

Population-based study.

SETTING

Medical Birth Registry of Norway and Statistics Norway.

POPULATION

We studied 169 583 low-risk primiparous mothers with singleton, cephalic labours, at ≥37 weeks of gestation, from 1999 to 2009.

METHODS

The associations between maternal age and mode of delivery were analysed using multinomial regression analyses, adjusting for sociodemographic factors.

MAIN OUTCOME MEASURES

Emergency caesarean section and operative vaginal delivery.

RESULTS

Of women aged ≥40 years, 22% had emergency caesarean sections and 24% had operative vaginal deliveries, giving adjusted relative risk ratios (RRRs) of 6.60 (95% confidence interval, 95% CI 5.53-7.87) and 3.30 (95% CI 2.79-3.90), respectively, when compared with women aged 20-24 years. Adjustments for sociodemographic factors only slightly changed the estimates. Dystocia was the main indication, followed by fetal distress. All of the listed factors increased the level of emergency operative deliveries, mainly because of an increase in dystocia. The increase in risk for emergency caesarean section by all factors, and for operative vaginal deliveries by epidural, were greater in older than in younger women, but were significant for epidural only.

CONCLUSIONS

We found a close association between maternal age and emergency operative delivery in low-risk primiparas. Contributory factors increased the risk for both emergency operative delivery and epidural more in older than in younger women.

Caesarean section--an appraisal of some predictive factors in Lagos Nigeria

Background

Several maternity units in the developing world lack facilities for caesarean section and often have to transfer patients in extremis. This case controlled study aimed to appraise predictive factors for caesarean section.

Methods

One hundred and fifty two consecutive women with singleton pregnancies who had caesarean section were studied. The next parturient with normal delivery served as control. Variables such as age, parity, marital status, booking status, past obstetric history, weight, height, infant birth weight were assessed. Data obtained were analysed using SPSS 16.0 Windows package.

Results

During the study period, there were 641 deliveries with 257 of them by caesarean section (40.1%).

Logistic regression analysis showed that parity, booking status, maternal height; maternal weight, birth weight, previous caesarean section and ante-partum bleeding were significant predictive factors for caesarean section while maternal age was not.

Conclusions

These predictive factors should be considered in antenatal counseling to facilitate acceptance by at risk women and early referral.

Adverse pregnancy outcomes related to advanced maternal age compared with smoking and being overweight

OBJECTIVE

To investigate the association between advanced maternal age and adverse pregnancy outcomes and to compare the risks related to advanced maternal age with those related to smoking and being overweight or obese.

METHODS

A population-based register study including all nulliparous women aged 25 years and older with singleton pregnancies at 22 weeks of gestation or greater who gave birth in Sweden and Norway from 1990 to 2010; 955,804 women were analyzed. In each national sample, adjusted odds ratios (ORs) of very preterm birth, moderately preterm birth, small for gestational age, low Apgar score, fetal death, and neonatal death in women aged 30-34 years (n=319,057), 35-39 years (n=94,789), and 40 years or older (n=15,413) were compared with those of women aged 25-29 years (n=526,545). In the Swedish sample, the number of additional cases of each outcome associated with maternal age 30 years or older, smoking, and overweight or obesity, respectively, was estimated in relation to a low-risk group of nonsmokers of normal weight and aged 25-29 years.

RESULTS

The adjusted OR of all outcomes increased by maternal age in a similar way in Sweden and Norway; and the risk of fetal death was increased even in the 30- to 34-year-old age group (Sweden n=826, adjusted OR 1.24, 95% confidence interval [CI] 1.13-1.37; Norway n=472, adjusted OR 1.26, 95% CI 1.12-1.41). Maternal age 30 years or older was associated with the same number of additional cases of fetal deaths (n=251) as overweight or obesity (n=251).

CONCLUSION

For the individual woman, the absolute risk for each of the outcomes was small, but for society, it may be significant as a result of the large number of women who give birth after the age of 30 years.

LEVEL OF EVIDENCE

II.

Experience of childbirth in first-time mothers of advanced age - a Norwegian population-based study

Background

Delaying the first childbirth to an advanced age has increased significantly during the last decades, but little is known about older first time mothers’ experience of childbirth. This study investigates the associations between advanced maternal age in primiparous women and the postnatal assessment of childbirth.

Methods

The study was based on the National Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health. Data on 30 065 nulliparous women recruited in the second trimester 1999–2008 were used. Three questionnaires were completed: around gestational week 17 and 30, and at 6 months postpartum. Medical data were retrieved from the national Medical Birth Register. Advanced age was defined as ≥32 years and the reference group as 25–31 years. Descriptive and multiple logistic regression analyses were conducted.

Results

Primiparous women aged 32 years and above expressed more worry about the upcoming birth than the younger women (adjusted OR 1.13; 95% CI 1.06-1.21), and 6 months after the birth they had a slightly higher risk of having experienced childbirth as ‘worse than expected’ (adjusted OR 1.09; 95% CI 1.02-1.16). The difference in birth experience was explained by mode of delivery. Comparisons within subgroups defined by the same mode of delivery showed that the risk of a more negative birth experience in the older women only applied to those with a spontaneous vaginal birth (adjusted OR 1.12; 95% CI 1.02-1.22). In women delivered by cesarean section, the older more often than younger women rated childbirth as ‘better than expected’ (elective cesarean delivery: adjusted OR 1.36; 95% CI 1.01-1.85, emergency cesarean delivery: adjusted OR 1.38; 95% CI 1.03-1.84).

Conclusion

Postponing childbirth to ≥32 years of age only marginally affected the experience of childbirth. Older women seemed to manage better than younger with having an operative delivery.

Obstetric and non-obstetric risk factors for cesarean section in oman

OBJECTIVE

This study aims to explore the risk factors, profiles and neonatal outcomes of Cesarean sections among selected women in Oman.

METHODS

In this hospital-based case-control study, a total of 500 participants (250 cases who had cesarean section and 250 controls who had spontaneous vaginal delivery), were randomly selected from four hospitals. Cases and controls were matched according to timing and place of delivery.

RESULTS

THE FOLLOWING PREDICTORS WERE FOUND TO BE SIGNIFICANTLY ASSOCIATED WITH INCREASED RISK OF CESAREAN SECTION: a) advancing age (above the age of 25 years, OR=1.42; p=0.03), b) prior cesarean section (previous cesarean section=1, OR=22.71; p=0.001), c) increased body mass index (obesity, OR=2.11; p=0.07), d) extremes of neonatal birth weight (neonates birth weight <2.5 kg, OR=5.2; neonates birth weight >4.0 kg, OR=7.3; p<0.001), and e) pre-pregnancy diabetes (OR=9.3; p=0.04). On the contrary, increased parity and history of the use of birth spacing methods (OR=0.38; p=0.03) were associated with decreased risk of cesarean section.

CONCLUSION

The study calls for increasing awareness about clinical and public health majors that would lead to prevention of risk factors associated with increased risk of cesarean section such as maintaining normal BMI and prevention of gestational and type 2 diabetes mellitus.

Caesarean section in nulliparous women of advanced maternal age has been reduced in Sweden and Norway since the 1970s: a register-based study

OBJECTIVE

To investigate rates of caesarean delivery in Sweden and Norway from 1973 to 2008 in relation to advanced and very advanced maternal age.

DESIGN

Register study.

SETTING

Sweden and Norway.

SAMPLE

All nulliparous women aged over 30 years with a singleton pregnancy, with the fetus in a cephalic presentation, and delivering at term between 1973 and 2008 were evaluated. The study population comprised 329 824 women in Sweden and 127 810 women in Norway.

METHODS

Data from the national Medical Birth Registers were used to describe caesarean section rates in three age groups: 30-34 years (reference group); 35-39 years (advanced age group); and ≥ 40 years (very advanced age group). Logistic regression analyses estimated the risk in each age group over four decades, in each of the two national samples.

RESULTS

Caesarean delivery decreased from 1973-1979 to 2000-2008 in the two oldest age groups in Sweden (35-39 years, OR = 0.53, 95% CI = 0.50-0.58; ≥ 40 years, OR = 0.36, 95% CI = 0.30-0.43) and Norway (35-39 years, OR = 0.61, 95% CI = 0.54-0.68; ≥ 40 years, OR = 0.45, 95% CI = 0.34-0.58), but increased in women aged 30-34 years. The caesarean delivery rate in the two oldest groups peaked in the second half of the 1970s. Regardless of time point, the caesarean delivery rate was always highest in women aged ≥ 40 years, followed by women aged 35-39 years and lowest in women aged 30-34 years.

CONCLUSIONS

Caesarean delivery in nulliparous women of advanced and very advanced age peaked by end of the 1970s in Sweden and Norway. The subsequent reduction was contemporaneous with the introduction of electronic fetal monitoring and a more consistent use of the partogram, suggesting that more effective surveillance of labour increased the chance of a vaginal birth in these high-risk women.

Births by Day of Week: A Historical Perspective

Our objective was to describe the historical pattern of the decline in weekend births. Data on 906,100 health maintenance organization enrollees' birthdates were analyzed to show patterns of birth by day of week from 1910 to 1999. The decline in Sunday births dates to the 1930s, and the decline in Saturday births dates to the 1950s, far earlier than previously demonstrated in the literature. The expected natural birth process has been significantly modified. By examining a much longer time series than in other literature, it is also possible to see that the trend is not abating and may be increasing.

Advanced maternal age and the risk of cesarean birth: a systematic review

BACKGROUND

The increasing pregnancy rate at advanced maternal age is contemporaneous with the increasing rate of cesarean birth. Several studies have found that advanced maternal age is a risk factor for cesarean birth. The objective of this systematic review was to assess the relationship between advanced maternal age and cesarean birth among nulliparous and multiparous women.

METHODS

To identify relevant studies, we searched the literature for articles published from January 1, 1995 to March 1, 2008, using Medline, EMBASE, PsychINFO, and CINAHL. We also hand-searched the bibliographies of retrieved articles to identify additional related studies. We included all cohort studies and all case-control studies that examined this association in developed countries. The Cochrane Collaboration's Review Manager software (5.0) was used to summarize the data.

RESULTS

Twenty-one studies met the inclusion criteria and were included in the review. All studies demonstrated an increased risk of cesarean birth among women at advanced maternal age compared with younger women, for both nulliparas and multiparas (relative risk varied from 1.39 to 2.76). Because we found extreme heterogeneity (both statistical and clinical) among the included studies, we did not provide a pooled estimate of the risk of cesarean birth.

CONCLUSIONS

All included studies illustrated an increased risk of cesarean birth among older women. Fifteen studies adjusted this association for potential confounders, which suggests that a valid and independent association is likely to exist between advanced maternal age and cesarean birth. However, the associated factors for this increased risk are not totally understood in the literature.

Age at menarche and the risk of operative first delivery

OBJECTIVE

The risk of operative delivery at term increases linearly with age at first birth. It has been hypothesised that this is because of a deleterious effect of a prolonged interval between menarche and first birth on uterine function. The aim of this study was to test a prediction from the hypothesis, namely, that the risk of operative first delivery would decline with later age at menarche.

DESIGN

Retrospective analysis of a prospective cohort study.

SETTING

The ALSPAC prospective cohort study enrolled pregnant women resident in Avon, UK with expected dates of delivery from 1 April 1991 to 31 December 1992.

POPULATION

A total of 3739 primipara recruited to the ALSPAC cohort who experienced labour at term with a singleton infant in a cephalic presentation.

MAIN OUTCOME MEASURE

Operative delivery, defined as caesarean section or operative vaginal birth.

RESULT

The rate of operative delivery was highest among women with age at menarche in the bottom quartile (32.4%, menarche aged <or=12) and was lower in the second (30.3%, menarche aged 13), third (29.2%, menarche aged 14) and top (26.9%, menarche aged >or=15) quartiles (test for trend, P = 0.01). When adjusted for height, body mass index, marital status, smoking status, induction of labour, week of gestation of delivery and birthweight percentile; the odds ratio for operative delivery associated with a 5-year increase in age at menarche (0.78, 95% CI 0.61-0.99) was very similar to the odds ratio for a 5-year decrease in age at delivery (0.73, 95% CI 0.67-0.79). There was no association between age at menarche and the risk of operative delivery following adjustment for the interval between menarche and the first birth (adjusted odds ratio 0.98, 95% CI 0.77-1.25).

CONCLUSION

Later menarche is associated with a decreased risk of operative delivery by decreasing the interval between menarche and first birth. The observation is consistent with the hypothesis that prolonged hormonal stimulation of the uterus prior to the first birth has a deleterious effect on uterine function.

Population-based standardization (PBS) of institutional cesarean delivery rates

BACKGROUND

Raw cesarean section rates are often compared among institutions with different patient populations. The purpose of this study was to develop an easily reproducible mathematical model that allows comparisons of cesarean delivery rates across different patient populations and institutions.

STUDY DESIGN

We first calculated three institution's cesarean delivery rates for each of ten groups of patients based on age and parity. The population based adjusted total cesarean delivery rate was then calculated for each institution based on the distribution of patients in the 2004 national birth data (n=4,097,029) but using the three institutions' individual cesarean delivery rates.

RESULTS

The adjusted for age and parity cesarean delivery rate was significantly lower from raw cesarean delivery rates in two of the three institutions (A: 28.2% adjusted vs. 36.5% raw; P=0; B: 28.2% adjusted vs. 30.4% raw, P=0.0411; C: 28.7% adjusted vs. 29.7% raw, NS) reflecting the older and more nulliparous patients in these two institutions.

CONCLUSIONS

Our study confirms that raw cesarean delivery rate should not be used to compare quality of care within and among different institutions unless they are adjusted for different patient characteristics. We believe that using unadjusted cesarean delivery rates without appropriate adjustments in quality assurance and when comparing data with other institutions and the national rate is erroneous and misleading.

The effect of delaying childbirth on primary cesarean section rates

BACKGROUND

The relationship between population trends in delaying childbirth and rising rates of primary cesarean delivery is unclear. The aims of the present study were (1) to characterize the association between maternal age and the outcome of labor, (2) to determine the proportion of the increase in primary cesarean rates that could be attributed to changes in maternal age distribution, and (3) to determine whether the contractility of uterine smooth muscle (myometrium) varied with maternal age.

METHODS AND FINDINGS

We utilized nationally collected data from Scotland, from 1980 to 2005, and modeled the risk of emergency cesarean section among women delivering a liveborn infant in a cephalic presentation at term. We also studied isolated myometrial strips obtained from 62 women attending for planned cesarean delivery in Cambridge, England, from 2005 to 2007. Among 583,843 eligible nulliparous women, there was a linear increase in the log odds of cesarean delivery with advancing maternal age from 16 y upwards, and this increase was unaffected by adjustment for a range of maternal characteristics (adjusted odds ratio for a 5-y increase 1.49, 95% confidence interval [CI] 1.48-1.51). Increasing maternal age was also associated with a longer duration of labor (0.49 h longer for a 5-y increase in age, 95% CI 0.46-0.51) and an increased risk of operative vaginal birth (adjusted odds ratio for a 5-y increase 1.49, 95% CI 1.48-1.50). Over the period from 1980 to 2005, the cesarean delivery rate among nulliparous women more than doubled and the proportion of women aged 30-34 y increased 3-fold, the proportion aged 35-39 y increased 7-fold, and the proportion aged > or =40 y increased 10-fold. Modeling indicated that if the age distribution had stayed the same over the period of study, 38% of the additional cesarean deliveries would have been avoided. Similar associations were observed in multiparous women. When studied in vitro, increasing maternal age was associated with reduced spontaneous activity and increased likelihood of multiphasic spontaneous myometrial contractions.

CONCLUSIONS

Delaying childbirth has significantly contributed to rising rates of intrapartum primary cesarean delivery. The association between increasing maternal age and the risk of intrapartum cesarean delivery is likely to have a biological basis.

Pregnancy outcome in primiparae of advanced maternal age

OBJECTIVE

To investigate the impact of maternal age on singleton pregnancy outcome, taking into account intermediate and confounding factors.

STUDY DESIGN

In this population-based retrospective cohort study, perinatal data of primiparous women aged 35 years or more (n = 2970), giving birth to a singleton child of at least 500 g, were compared to data of primiparous women aged 25-29 years old (n = 23,921). Univariate analysis was used to assess the effect of maternal age on pregnancy outcomes. The effects of intermediate (hypertension, diabetes and assisted conception) and confounding factors (level of education) were assessed through multivariable logistic regression analysis.

RESULTS

Older maternal age correlated, independently of confounding and intermediate factors, with very preterm birth (gestational age <32 weeks) [adjusted odds ratio (AOR) 1.51, 95% confidence intervals (CI) 1.04-2.19], low birth weight (birth weight <2500 g) (AOR 1.69, 95% CI 1.47-1.94) and perinatal death (AOR 1.68, 95% CI 1.06-2.65).

CONCLUSION

Maternal age is an important and independent risk factor for adverse pregnancy outcome.

Delayed parenthood and the risk of cesarean delivery--is paternal age an independent risk factor?

BACKGROUND

Between 1995 and 2001, the average cesarean section rates in Taiwan were as high as 33.34 percent. This study set out to determine the independent effects of paternal age on the likelihood of cesarean delivery among a sample of Taiwanese women.

METHODS

Logistic regressions were used to analyze 310,574 singleton deliveries by nulliparous women in Taiwan between 1999 and 2001, linking data abstracted from birth certificates and from the National Health Insurance claims database. After controlling for socioeconomic, pregnancy, and obstetric complications, as well as institutional factors, we investigated both maternal and paternal ages simultaneously, using the single category variable "parental age" to determine the differential age effects on the risk of cesarean delivery.

RESULTS

Taking 20- to 29-year-old couples as the reference group, we observed that the relative risks of cesarean delivery become progressively higher with advancing age of the mother. At the same time, within each maternal group, positive and significant variations in cesarean rates occurred for different paternal age groups. The respective increases in the relative risks of cesarean delivery for men aged 20-29, 30-34, 35-39, and 40 years or more, in conjunction with women aged 20-29, 30-34 and 35 or over, are 34 percent from 1.00 to 1.34, 18 percent from 1.51 to 1.69, and 16 percent from 2.03 to 2.19. Other confounding variables are also taken into account.

CONCLUSIONS

Irrespective of maternal age, advancing paternal age also appears to be an additional independent factor that has a strong association with the increase in cesarean section rates.

[Pregnancy beyond age 40 in 382 women: a retrospective study in Reunion Island]

OBJECTIVE

To examine obstetrical and neonatal outcomes among women age 40 years and older.

MATERIAL AND METHODS

There was a retrospective study including 382 pregnant women at least 40 years of age and 7786 controls aged 20-34, stratified according to parity. Associations between maternal age and pregnancy outcomes were assessed using Pearson's chi(2) test, Fischer exact test, Student test or Mann and Whitney test, as appropriate.

RESULTS

Maternal age 40 and over was associated with an increased risk for gestational diabetes (multiparas: OR 3.2, 95%CI 2.2-4.8; grandmultiparas: 2.8, 1.6-5.0), chronic diabetes (multiparas: 3.5, 1.04-10.6), chronic hypertension (multiparas: 3.1, 1.5-6.1; grandmultiparas: 12.1, 3.3-53.2), pregnancy-induced hypertension (nulliparas: 4.6, 1.01-17.3; multiparas: 2.6, 1.3-5.4) and preclampsia (multiparas: 2.9, 1.1-7.2). The risk for cesarean section was 2-fold higher in older multiparas and grandmultiparas. The same was true for the rate of operative vaginal delivery. The rate of fetal chromosomal abnormalities was 7-fold higher in older gravidas. Rates of fetal death were significantly increased in the cohort of older pregnant women (nulliparas: 11.2, 2.9-44.0; multiparas: 3.9, 1.4-10.9).

CONCLUSION

Pregnancy at age 40 and over is associated with high rates of obstetrical complications, cesarean sections and operative vaginal deliveries, emphasizing the importance of rigorous antenatal care.

Prenatal risk factors for Caesarean section. Analyses of the ALSPAC cohort of 12,944 women in England

BACKGROUND

There has been an escalation in Caesarean section rates globally. Numerous prenatal factors have been associated with elective and emergency Caesarean section, some of which may be amenable to change.

METHODS

A population-based cohort of 12,944 singleton, liveborn, term pregnancies were used to investigate risk factors for Caesarean section using multivariable logistic regression modelling. Numerous prenatal factors were investigated for their associations with the following outcomes: first, with Caesarean section (both elective and emergency) compared with vaginal delivery (spontaneous and assisted); second, for their associations with elective Caesarean section compared with attempted vaginal delivery; and finally emergency Caesarean section compared with spontaneous vaginal delivery.

RESULTS

11,791 women had vaginal delivery and 1153 had Caesarean section (685 emergency, 468 elective). Non-cephalic (breech) presentation (all Caesareans odds ratio (OR) 36.6, 95% confidence interval (CI) 26.8-50.0; elective Caesarean OR 86.4, 95% CI 58.5-127.8; emergency Caesarean OR 9.58, 95% CI 6.06-15.1) and previous Caesarean section (all Caesareans OR 27.8, 95% CI 20.9-37.0, elective Caesarean OR 54.4, 95% CI 38.4-77.5; emergency Caesarean OR 13.0, 95% CI 7.76-21.7) were associated in all analyses with an increased risk of Caesarean section. Extremes of neonatal birthweight were associated with an increased risk of Caesarean section (all Caesareans and emergency section) compared with vaginal delivery as was increasing neonatal head circumferences. In all analyses increasing maternal age (OR 1.07 per year, 95 % CI 1.04-1.09; OR 1.04 per year, 95 % CI 1.01-1.08; OR 1.11 per year, 95% CI 1.08-1.15) was independently associated with increased odds of Caesarean section. Increasing parity was associated with a decrease in risk for all Caesareans and emergency section (OR 0.63, 95% CI 0.53-0.75 and OR 0.46, 95% CI 0.33-0.63, respectively), as was the outcome of the last pregnancy being a live child. Increasing gestation was independently associated with a decreased risk of both all Caesareans and elective Caesarean (OR 0.86, 95% CI 0.80-0.93 and OR 0.52, 95% CI 0.46-0.58 respectively), whereas diabetes mellitus was associated with increased risk. These variables were not associated with emergency section. However, epidural use was associated with an increased risk of emergency Caesarean (OR 6.49, 95% CI 4.78-8.82) while being in a preferred labour position decreased the risk (OR 0.59, 95% CI 0.49-0.73).

CONCLUSIONS

A careful exploration of risk factors may allow us to identify reasons for the increasing rates of Caesarean section and the marked variation between institutions.