title: Estimating the impact of pelvic immaturity and young maternal age on fetal malposition.
abstract: OBJECTIVE
  Fetal malposition, specifically occiput posterior and transverse (OP/OT), is associated with higher intra-partum morbidity. We tested the hypothesis that young maternal age and pelvic immaturity are risk factors for fetal malposition.
  
  
  METHODS
  In a cohort study of all nulliparous teen (≤18 years) deliveries over a 4-year period at one institution, fetal head position at time of delivery was collected and correlated with maternal characteristics and outcome data. Using Risser staging observations, pelvic maturity age was set at 16, and accordingly, the women were divided into two groups (younger vs. older teens). Analysis was performed using Fisher's exact, student t test, and logistic regression modeling.
  
  
  RESULTS
  Older teen mothers (16-18 years, n = 609) had higher rates of malposition (22 vs. 12 %, p = 0.02) when compared with younger teens (≤15 years, n = 98). Among all women with a malpositioned fetus, older teens had a higher body mass index (BMI: 32.6 ± 6.7 vs. 28.5 ± 3.5, p = 0.04) and subsequent need for cesarean delivery (69 vs. 33 %, p = 0.02) when compared with their younger counterparts. Although younger teens were more successful in having a vaginal delivery (67 %) with an OP/OT position, it was at the expense of a 25 % rate of severe perineal laceration (third/fourth degree).
  
  
  CONCLUSIONS
  Obesity, and not young maternal age or pelvic immaturity, is associated with fetal malposition. The direct association with increasing pre-pregnancy BMI and the long-term impacts of the high rates of cesarean delivery in this young population underscores the need for more public health focus.
authors.affiliation: Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Baylor College of Medicine and Texas Children's Hospital, One Baylor Plaza, MS: BCM 610, Houston, TX 77030, USA. SinaHaeri@Gmail.com
authors.forename: Sina
authors.initials: S
authors.lastname: Haeri
authors.forename: Arthur M
authors.initials: AM
authors.lastname: Baker
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D005260:Female; D006801:Humans; D007746:Labor Presentation; D008423:Maternal Age; D009765:Obesity / Q000150:complications; D007744:Obstetric Labor Complications / Q000209:etiology*; D010388:Pelvis / Q000254:growth & development; D011247:Pregnancy; D011253:Pregnancy in Adolescence; D012189:Retrospective Studies; D012307:Risk Factors