title: Influence of duration of sexual cohabitation on the risk of hypertension in nulliparous parturients in Ibadan: A cohort study.
abstract: BACKGROUND
  Hypertensive disorders of pregnancy are an important cause of maternal mortality in this environment, it accounts for about 20% of all maternal deaths in pregnancy in Nigeria.
  
  
  OBJECTIVE
  This study aims to determine the effect of the length of sexual cohabitation on the development of hypertension in pregnancy in a Nigerian population.
  
  
  METHODS
  The study was a prospective cohort study; three centres were involved in the study between July 2006 and February 2009. For this study, the main outcome variable was the development of Hypertension in pregnancy. The main explanatory variable was the length of preconception sexual cohabitation. Univariate analysis was by t test, chi-squared test and Fisher's exact test for continuous and categorical variables. Multivariate analysis was by Cox hazard regression.
  
  
  RESULTS
  In the study population, the incidence of gestational hypertension and pre-eclampsia were 28.93% and 4.13% respectively, 29.64% had previous abortions and same paternity abortion rate was 25.92%. Length of sexual cohabitation before index pregnancy was protective against hypertension in pregnancy but not for pre-eclampsia; there was a 4% decrease in the risk of developing hypertension for every month increase in cohabitation (hazard ratio, HR 0.96 (95% CI 0.93-0.99)). Also protective in this model was same paternity abortion with a HR of 0.71 (95% CI 0.55-0.93). A previous abortion was not protective (HR 1.05 (95% CI 0.82-1.35)).
  
  
  CONCLUSIONS
  It was concluded that increased length of sexual cohabitation prior to conception reduces the risk of gestational hypertension.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Ibadan, Nigeria. oladapo.olayemi@yahoo.com
authors.forename: Oladapo
authors.initials: O
authors.lastname: Olayemi
authors.forename: Donna
authors.initials: D
authors.lastname: Strobino
authors.forename: Christopher
authors.initials: C
authors.lastname: Aimakhu
authors.forename: Kayode
authors.initials: K
authors.lastname: Adedapo
authors.forename: Aderemi
authors.initials: A
authors.lastname: Kehinde
authors.forename: Akin-Tunde
authors.initials: AT
authors.lastname: Odukogbe
authors.forename: Babatunde
authors.initials: B
authors.lastname: Salako
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000453:epidemiology*; D015994:Incidence; D008297:Male; D009549:Nigeria / Q000453:epidemiology; D010298:Parity; D011225:Pre-Eclampsia / Q000453:epidemiology; D011247:Pregnancy; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012725:Sexual Behavior; D012747:Sexual Partners; D013997:Time Factors; D055815:Young Adult