[Sensible family planning: do not have children too late, but not too early either]. / Verstandige gezinsplanning: niet te laat, maar ook niet te vroeg kinderen krijgen.

Due to family planning, Dutch women are increasingly having their first child between 25 and 35 years of age. Compared to 13 other EU countries, Dutch women are having fewer children both earlier and later on in life. From 1970 onwards in the Netherlands, the mean age at first childbirth has increased by 5 years to 29.4 years. The main cause for the rising age at first childbirth is the decrease in the number of young mothers. In 2006, 7% of all childbearing women had their first child after the age of 36; this is just 4.7% higher than in 1970. The percentage of women remaining childless by delaying childbearing too long increased by 0.9%. Considering the social and medical problems in later life, it would not be wise to encourage women to have their babies at a young age, certainly not before the age of 23. Women planning a family should take into account the decline in natural fertility after the age of 35; the future mothers of the Netherlands seem to be planning and deciding wisely.

Selective association of multiple sclerosis with infectious mononucleosis.

Previous studies have suggested an association between multiple sclerosis (MS) and infectious mononucleosis (IM) but data on the exact strength of this association or its selectivity have been conflicting. In this study we have evaluated the association between MS and a variety of common childhood infections and afflictions in a large population-based case-control study involving 2,877 MS cases and 2,673 controls in the Netherlands. We examined the frequency of different common infections and afflictions before the age of 25 and the age at which they occurred, using a self-administered questionnaire. The Odds ratios (ORs) for the occurrence of a variety of clinically manifest common childhood infections including rubella, measles, chicken pox and mumps before the age of 25 for MS cases versus controls ranged between 1.14 and 1.42, values similar to those for irrelevant probe variables used to reveal recall bias. In contrast, the OR for clinically manifest IM in MS cases versus controls, corrected for demographic variables, was 2.22 (95% confidence interval 1.73 - 2.86; P < 0.001). The average age of onset of IM in the population of MS cases (16.5 years) did not differ from controls (16.8 years). Our data confirm previous much smaller studies to show that the risk for MS is significantly enhanced by prior IM, and extend those previous data by showing that this association is far stronger than with other common childhood infections or afflictions.

Women's interest in GP-initiated pre-conception counselling in The Netherlands.

BACKGROUND: Pre-conception counselling has the potential to reduce pregnancy complications and congenital disorders. The timing of counselling, before conception, is crucial to maximize the benefit. As many couples are unaware of their risk status and the fact that the first period of pregnancy is crucial, they do not seek information before pregnancy occurs. To reach couples with timely information, it seems that a health care worker needs to take the initiative. In The Netherlands, the GP is in an ideal position to offer pre-conception counselling. OBJECTIVE: The aim of this study was to determine the interest of women aged 18-40 in pre-conception counselling if this is offered to them by their own GP. METHOD: A cohort of women (n = 1206) received a personal letter from their own GP with an offer of pre-conception counselling. The women were requested to fill in a reply form, indicating if they were interested, might be interested (if they decided to become pregnant) or were not interested in an invitation for pre-conception counselling. When interested, they were asked to give an indication as to when they were planning a pregnancy. Women who were not interested were requested to give a reason. RESULTS: Almost 70% of the women returned the reply form. Up to the age of 29 years, at least 80% of the respondents were interested or might be interested should they decide to have children. Most women, especially the younger women, do not know exactly when they wish to become pregnant. Regardless of age, >70% of the respondents were interested. Only 11% of the respondents indicated specifically that they were not interested in advice. CONCLUSION: Women are interested in GP-initiated pre-conception counselling. Further research is needed to assess the effect of programmed and systematic pre-conception counselling, offered by GPs, on pregnancy outcome and the health of the children. A randomized controlled trial to assess these effects currently is being conducted at the Department of General Practice in Leiden.

Space-time clustering of multiple sclerosis cases around birth.

OBJECTIVES: To investigate whether infectious events around birth and during early infancy are likely to be of relevance in MS pathogenesis. SUBJECTS AND METHODS: Data are available from two regions in The Netherlands: Groningen (n=320) and Rotterdam (n=226). Simultaneous clustering in birth date and birth location of MS cases is tested by the methods of Mantel, Knox and Jacquez. RESULTS: No evidence was found for a space-time interaction between place and time of birth. CONCLUSION: Perinatal infectious events are unlikely to be a major factor in determining MS susceptibility.

Maternal smoking during lactation: relation to growth during the first year of life in a Dutch birth cohort.

A recent article by Little et al. (Am J Epidemiol 1994;140:544-54) reported that infants in Seattle, Washington, who were breastfed by mothers who smoked gained more weight than either infants who were breastfed by mothers who did not smoke or infants who were bottle-fed by mothers who smoked. In this study, the authors aimed to verify this result with the use of data from the Social Medical Survey of Children Attending Child Health Clinics (SMOCC) cohort, a nationally representative cohort of 2,151 children born in the Netherlands in 1988-1989. During the first year of life, data on type of milk feeding, weight, length, and head circumference were collected at 1, 2, 3, 6, 9, and 12 months of age. Infants of smokers who were mainly breastfed in the first 3 months of life (n = 117) were compared with similarly breastfed infants of nonsmokers (n = 572), with infants of smokers who had been mainly bottle-fed (n = 270), and with infants of nonsmokers who had been mainly bottle-fed (n = 535). The authors failed to observe any additional increase in body mass, length, or head circumference in infants of breastfeeding smokers compared with infants of the three other groups. When the authors used all of their data to study growth with a multivariate longitudinal regression model (general estimating equations (GEE) model), the data showed clearly reduced growth in breastfed children (limited to the period after the second month of life) and some "catch-up" growth in body mass and head circumference in children with intrauterine exposure to tobacco.

Dieting, weight and health in adolescents in The Netherlands.

OBJECTIVE: To estimate the prevalence of dieting and the relationship between dieting, nutritional habits, and health among young adolescents in the Netherlands. METHODS: Out of 1359 secondary school children, aged 13 through 15 y, who were invited for a routine health assessment by school doctors or nurses as part of the Child Health Monitoring System, 1279 (94%) responded and data were analyzed. RESULTS: Among secondary school children 13% of girls and 5% of boys were dieting at the time of the health assessment. Half of the dieting pupils were at risk of overweight, while the other half were within the normal weight range. The mean preferred weight of the dieting pupils was not lower than the mean actual weight of the non-dieting pupils. Dieting pupils skipped meals more often and consumed less sweets and salty snacks, soft drinks and bread than non-dieting pupils. School absence due to illness was relatively high in dieting boys, and medicine use was high in dieting girls. CONCLUSION: As in other Western countries, dieting is a common practise among young adolescents in the Netherlands, especially in girls. "Unhealthy' dietary practices, like skipping breakfast, are already present at early age, therefore preventive programs should be targeted at young adolescents.

Moderate drinking: no impact on female fecundity.

OBJECTIVE: To determine the effect of moderate alcohol intake on probability of conception. DESIGN: Prospective cohort study. SETTING: Normal healthy women enrolled in an artificial donor insemination program. PATIENTS: Women starting artificial donor insemination for the very first time were selected. INTERVENTIONS: Alcohol exposure was measured through a self-administered questionnaire at intake of study. MAIN OUTCOME MEASURE: A first positive pregnancy test as indicative for conception. RESULTS: Women with moderate alcohol intake had a slightly higher, though not significant, probability of conception compared with nondrinkers (Hazard Ratio 1.20; 95% confidence interval 0.90 to 1.60). CONCLUSION: Moderate alcohol intake has no negative impact on female fecundity.

Social class, ethnicity and other risk factors for small for gestational age and preterm delivery in The Netherlands.

Social class and ethnicity are important risk factors for small-for-gestational-age and preterm delivery in many countries. This study was performed to assess whether this is also the case in the Netherlands, a country with a high level of social security, relatively small income differences and easy access to medical care for all its inhabitants. Other risk factors that were taken into account were smoking, drinking, occupation, age and height. Information was collected by interview in the first 3 weeks of life of the mothers of 2027 (response 97%) live-born singletons born in the period from April 1988 to October 1989 in the study area. After adjustment for possible confounding factors very low social class, compared with high social class, was significantly associated with reduced birthweight (-4.0%; 95% CI, -7.4% to -0.7%), but not with preterm delivery (OR, 2.09; 95% CI, 0.67-6.48). The adjusted birthweight of Turkish infants (2.7%; 95% CI, -1.1% to 6.5%) and the adjusted birthweight of infants from Suriname or the Antilles (-1.6%; 95% CI, -5.5% to 2.1%) were not significantly different compared with infants of Dutch mothers. After adjustment, the frequency of preterm birth was lower in Turkish infants, but not significantly (OR, 0.22; 95% CI, 0.04-1.10), whereas the frequency of preterm birth in infants from Suriname or the Antilles was significantly higher (OR, 2.51; 95% CI, 1.04-6.08) compared with Dutch infants. Of the other factors the main risk factors were smoking (negatively related with birth-weight) and maternal age(ABSTRACT TRUNCATED AT 250 WORDS)

[Relationship between socioeconomic status and differences in health care utilization in pregnancy, delivery and puerperium]. / Verband tussen sociaal-economische status en verschillen in gebruik van zorg bij zwangerschap, bevalling en kraamperiode.

OBJECTIVE: Description of differences in pre-, peri- and postnatal care, according to socio-economic status (SES). SETTING: Geographically defined areas of 21 child health clinics (CHC) in several parts of the Netherlands. DESIGN: Retrospective cohort study. MATERIALS AND METHOD: Of all women who delivered a live-born child in the period April 1988-October 1989 and who were residents of the districts of the CHCs (n = 2119), data were recorded during the home visit post partum by the district nurses. Complete data were available of 2060 (97.2%) mothers. The care provided was defined as prenatal care and attendance at delivery (midwife, general practitioner, obstetrician and combinations), place and mode of delivery, and place of lying-in period. The indicator for SES was the educational level of the mother. In multivariate analyses, age, parity, degree of urbanisation of residential area, distance between home and hospital, ethnicity, height, smoking, health problems during pregnancy, obstetrical history, preterm birth and low birth weight were included in order to correct for possible confounding effects of these factors. RESULTS: Compared to the higher SES group, there was an increased risk in the lower SES group for a delivery in hospital (OR 1.60; 95% CI 1.16-2.20); the probability of having a complete lying-in period at home decreased according to the SES level (low SES: OR 0.47; 95% CI 0.34-0.65). Differences in mode of delivery (notably caesarean section) were very small and not significant. CONCLUSIONS: In the Netherlands there are socio-economic differences in perinatal care and the place of the lying-in period. Women of higher SES delivered more often at home and more often had their lying-in period at home, irrespective of other factors. Preferences of the mothers with respect to place of confinement were not taken into account in this study.

The effect of moderate maternal alcohol consumption on birth weight and gestational age in a low risk population.

We analyzed the relationship between moderate maternal alcohol consumption during pregnancy and both birth weight corrected for gestational age and preterm delivery in 3447 women. Information on alcohol consumption in the first and second trimester was obtained during mid pregnancy and information about third trimester drinking was obtained a few days after delivery. After adjustment for possible confounders we found that for most women alcohol consumption was unrelated to birth weight corrected for gestational age and preterm delivery. However, in the subgroup of women smoking 20 cigarettes or more a day, drinking more than 120 g alcohol a week in early pregnancy was associated with a 7.2% (95% CI 0.2% to 14.2%) decrease in birth weight. We conclude that the effect of alcohol use on birth weight corrected for gestational age and gestational age is limited. However, in women who smoke heavily, a reported consumption of about two drinks or more a day in early pregnancy may be an additional risk factor for impaired fetal growth.

Fat and female fecundity: prospective study of effect of body fat distribution on conception rates.

OBJECTIVES: To study the effect of body fat distribution in women of reproductive age on fecundity. DESIGN: Prospective cohort study of all women who had entered a donor insemination programme. SETTING: One fertility clinic serving a large part of the midwest of the Netherlands. SUBJECTS: Of 542 women attending the clinic for artificial insemination for the first time, 500 women were eligible for study. MAIN OUTCOME MEASURES: Probability of conception per cycle and number of insemination cycles before pregnancy or stopping treatment. RESULTS: A 0.1 unit increase in waist-hip ratio led to a 30% decrease in probability of conception per cycle (hazard ratio 0.706; 95% confidence interval 0.562 to 0.887) after adjustment for age, fatness, reasons for artificial insemination, cycle length and regularity, smoking, and parity. Increasing age was significantly related to lower fecundity (p < 0.05); very lean and obese women were less likely to conceive (p < 0.10) as were women with subfertile partners (p < 0.10). All other exposure variables were not significantly related to fecundity. CONCLUSIONS: Increasing waist-hip ratio is negatively associated with the probability of conception per cycle, before and after adjustment for confounding factors. Body fat distribution in women of reproductive age seems to have more impact on fertility than age or obesity.

Delaying childbearing: effect of age on fecundity and outcome of pregnancy.

OBJECTIVES: To study the age of the start of the fall (critical age) in fecundity; the probability of a pregnancy leading to a healthy baby taking into account the age of the woman; and, combining these results, to determine the age dependent probability of getting a healthy baby. DESIGN: Cohort study of all women who had entered a donor insemination programme. SETTING: Two fertility clinics serving a large part of The Netherlands. SUBJECTS: Of 1637 women attending for artificial insemination 751 fulfilled the selection criteria, being married to an azoospermic husband and nulliparous and never having received donor insemination before. MAIN OUTCOME MEASURES: The number of cycles before pregnancy (a positive pregnancy test result) or stopping treatment; and result of the pregnancy (successful outcome). RESULTS: Of the 751 women, 555 became pregnant and 461 had healthy babies. The fall in fecundity was estimated to start at around 31 years (critical age); after 12 cycles the probability of pregnancy in a woman aged greater than 31 was 0.54 compared with 0.74 in a woman aged 20.31. After 24 cycles this difference had decreased (probability of conception 0.75 in women greater than 31 and 0.85 in women 20.31). The probability of having a healthy baby also decreased--by 3.5% a year after the age of 30. Combining both these age effects, the chance of a woman aged 35 having a healthy baby was about half that of a woman aged 25. CONCLUSION: After the age of 31 the probability of conception falls rapidly, but this can be partly compensated for by continuing insemination for more cycles. In addition, the probability of an adverse pregnancy outcome starts to increase at about the same age.

PIP: This study examined the age of the start of the fall (critical age) in fecundity, the probability of a pregnancy leading to a healthy baby taking into account the age of the women, and, by combining all of the results, the determination of the age-dependent probability of getting a healthy baby. 2 fertility clinics serving a large part of the Netherlands provided the 751 women who fulfilled the selection criteria. In this cohort study of all women who entered a donor insemination program, those who fulfilled the selection criteria were married to azoospermic husbands, were nulliparous, and never received donor insemination previously. Main outcome measures studied were the number of cycles prior to a pregnancy (positive pregnancy result) or the cessation of treatment and the result of the pregnancy (successful outcome). Of 751 women, 555 became pregnant and 461 had healthy babies. The drop in fecundity was estimated to begin at around age 31 (critical age); after 12 cycles, the probability of pregnancy in a woman age 31 was 0.54 compared with 0.74 in a woman age 20-31. After 24 cycles, this difference had decreased (probability of conception 0.75 in women 31 and 0.85 in women age 20-31). The probability of having a healthy baby also decreased, by 3.5% a year after the age of 30. Combining both of these age effects, the chance of a woman age 35 having a healthy baby was about 1.2 that of a woman age 25. After the age of 31, the probability of conception falls rapidly; however, this can be compensated for partly by continuing insemination for more cycles. In addition, the probability of an adverse pregnancy outcome begins to increase at about the same age.

The study of risk habits in reproductive and perinatal epidemiologic research: the use of a donor inseminated population of women.

In this study we assess whether a population of donor inseminated women (ADI) provides an efficient alternative to an open population of women of reproductive age to study the effects of risk habits (cigarette smoking and alcohol consumption) on reproductive and perinatal health. An ADI population can be prospectively monitored before and after pregnancy; women enter the programme because of their husband's infertility. In the pilot clinic every couple asking for first insemination was requested to fill in a self-administered questionnaire on risk habits and the use of medicine. Medical histories of both the man and woman were taken. In 1986 and 1987, 519 women entered the programme. The response rate was 95%. Distribution of the exposure variables of the women currently smoking (52%) and currently drinking (68%) compared well with a general population survey from the town of Rotterdam. With regard to their risk habits and reproductive health, the population of women married to totally infertile men seems representative of women of reproductive age from an open population.