Interpregnancy interval and the risk of preterm birth in Thrace, Greece.

OBJECTIVE: To examine the influence of short interpregnancy interval on the prevalence of preterm birth in two, ethically different, Greek populations. STUDY DESIGN: We studied 652 urban Christian women and 578 rural, Romany, Muslim women who had had two consecutive, singleton pregnancies. We related the prevalence of preterm birth to the interpregnancy intervals (cut-off point, 6 months). Student's t-test, x(2)-test and relative risk estimation were used. RESULTS: Preterm birth and interpregnancy intervals less than 6 months occurred more often among Muslims than Christians. Among Muslims, an interval of <6 months was associated with greater prevalence of preterm birth (16% versus 7.3%, P=0.013, RR=2.4 and 95% C.I. 1.3-4.7). Christians did not demonstrate a similar relationship. CONCLUSIONS: A short interpregnancy interval seems to be a risk factor for preterm birth in the population of rural, Romany, Muslim women.

Cytogenetic evaluation of pre-pregnancy smoking in maternal and newborn lymphocytes.

OBJECTIVE: To study cytogenetic damage in order to estimate the effect of pre-pregnancy smoking on pregnant women and their foetuses. STUDY DESIGN: Lymphocyte cultures were obtained from peripheral blood of 20 women who quit smoking during pregnancy, and umbilical cord blood of their newborns at delivery. Cytogenetic analyses were performed for sister chromatid exchanges (SCEs), proliferation rate index (PRI) and mitotic index (MI) using the Fluorescence Plus Giemsa staining technique. Twenty non-smoking women and their newborns were evaluated as controls. CPT-11, a known antineoplastic, was used as a positive genotoxic agent in order to correlate non-smoking women with smoking women and reveal any underlying chromosome instability. Statistical evaluation of SCE frequencies, PRI and MI was based on independent samples t-test in order to estimate the effect of pre-pregnancy smoking on mothers and their newborns. RESULTS: SCEs were induced in the cord blood lymphocytes of newborns whose mothers smoked before pregnancy when they were exposed to the mutagenic agent CPT-11 (p<0.01). A similar increase in SCEs was observed in both non-smoking and smoking mothers exposed to CPT-11. Newborns in both groups had significantly lower SCE levels than their mothers (p<0.01). CONCLUSION: Pre-pregnancy smoking results in cytogenetic damage for both mothers and newborns, and is an important risk factor for cancer and/or other genetic-related diseases. Smoking cessation needs to occur well before conception in order to avoid the strong cytogenetic association between pre-pregnancy smoking by mothers and their newborns.