Article| Volume 25, ISSUE 7, 100845, July 2023

Route of delivery does not impact postnatal surgical morbidity in pregnancies affected by fetal achondroplasia

Published:April 12, 2023DOI:



      Pregnancies affected by maternal or fetal achondroplasia present unique challenges. The optimal route of delivery in fetuses with achondroplasia has not been established. Our objective was to determine whether the route of delivery affects postnatal achondroplasia–related surgical burden.


      We conducted a secondary analysis of Achondroplasia Natural History Study (CLARITY), which is a multicenter natural history cohort study of patients with achondroplasia. Achondroplasia-related surgical morbidity, which we defined as the need for one or more postnatal achondroplasia–related surgeries, was assessed in relation to the route of delivery and whether the mother also had achondroplasia. Rate of each individual surgery type (otolaryngology, brain, foramen magnum, spine, and extremity) was also assessed in relation to the route of delivery.


      Eight hundred fifty-seven patients with achondroplasia with known route of delivery and known maternal stature were included. Three hundred sixty (42%) patients were delivered vaginally, and 497 (58%) patients were delivered by a cesarean delivery. There was no difference in the odds of requiring any postnatal achondroplasia–related surgery in those with achondroplasia who were delivered vaginally compared with those delivered by cesarean birth (odds ratio 0.95, 95% CI = 0.68-1.34, P = .80). No difference was present in the odds of requiring any postnatal achondroplasia–related surgery when route of delivery was compared for fetuses born to 761 average stature mothers (odds ratio 1.05, 95% CI = 0.74-1.51, P = .78). There was also no difference in the odds of requiring each of the individual achondroplasia-related surgeries by route of delivery, including cervicomedullary decompression.


      Our study suggests that it is reasonable for average stature patients carrying a fetus with achondroplasia to undergo a trial of labor in the absence of routine obstetric contraindications.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      ACMG Member Login

      Are you an ACMG Member? Sign in for online access.


      Subscribe to Genetics in Medicine
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Coi A.
        • Santoro M.
        • Garne E.
        • et al.
        Epidemiology of achondroplasia: A population-based study in Europe.
        Am J Med Genet A. 2019; 179: 1791-1798
        • Legare J.M.
        Achondroplasia. GeneReviews. Seattle.
        University of Washington, Washington1998
        • Hoover-Fong J.E.
        • Alade A.Y.
        • Hashmi S.S.
        • et al.
        Achondroplasia Natural History Study (CLARITY): a multicenter retrospective cohort study of achondroplasia in the United States.
        Genet Med. 2021; 23: 1498-1505
        • Pauli R.M.
        • Scott C.I.
        • Wassman Jr., E.R.
        • et al.
        Apnea and sudden unexpected death in infants with achondroplasia.
        J Pediatr. 1984; 104: 342-348
        • Hecht J.T.
        • Nelson F.W.
        • Butler I.J.
        • et al.
        Computerized tomography of the foramen magnum: achondroplastic values compared to normal standards.
        Am J Med Genet. 1985; 20: 355-360
        • Pauli R.M.
        • Horton V.K.
        • Glinski L.P.
        • Reiser C.A.
        Prospective assessment of risks for cervicomedullary-junction compression in infants with achondroplasia.
        Am J Hum Genet. 1995; 56: 732-744
        • Zanelli S.
        Skeletal dysplasia treatment & management: medical care, surgical care, consultations.
        Medscape, 2020 (
        • Savarirayan R.
        • Rossiter J.P.
        • Hoover-Fong J.E.
        • et al.
        Best practice guidelines regarding prenatal evaluation and delivery of patients with skeletal dysplasia.
        Am J Obstet Gynecol. 2018; 219: 545-562
        • Vivanti A.J.
        • Cordier A.G.
        • Baujat G.
        • Benachi A.
        Abnormal pelvic morphology and high cervical length are responsible for high-risk pregnancies in women displaying achondroplasia.
        Orphanet J Rare Dis. 2016; 11: 166
        • Tyson J.E.
        • Barnes A.C.
        • McKusick V.A.
        • Scott C.I.
        • Jones G.S.
        Obstetric and gynecologic considerations of dwarfism.
        Am J Obstet Gynecol. 1970; 108: 688-704
        • Harris P.A.
        • Taylor R.
        • Thielke R.
        • Payne J.
        • Gonzalez N.
        • Conde J.G.
        Research Electronic Data Capture (REDCap)--a metadata-driven methodology and workflow process for providing translational research informatics support.
        J Biomed Inform. 2009; 42: 377-381
        • Jenko N.
        • Connolly D.J.A.
        • Raghavan A.
        • et al.
        The (extended) achondroplasia foramen magnum score has good observer reliability.
        Pediatr Radiol. 2022; 52: 1512-1520
        • Hecht J.T.
        • Francomano C.A.
        • Horton W.A.
        • Annegers J.F.
        Mortality in achondroplasia.
        Am J Hum Genet. 1987; 41: 454-464
        • Bland J.D.
        • Emery J.L.
        Unexpected death of children with achondroplasia after the perinatal period.
        Dev Med Child Neurol. 1982; 24: 489-492
        • Parente M.P.
        • Natal Jorge R.M.
        • Mascarenhas T.
        • Fernandes A.A.
        • Silva-Filho A.L.
        Computational modeling approach to study the effects of fetal head flexion during vaginal delivery.
        Am J Obstet Gynecol. 2010; 203: 217.e1-217.e6
        • QuickStats
        Rate of cesarean delivery, by maternal prepregnancy body mass index category∗ - United States, 2020.
        MMWR Morb Mortal Wkly Rep. 2021; 70: 1686
        • Caughey A.B.
        • Cahill A.G.
        • Guise J.M.
        • Rouse D.J.
        Safe prevention of the primary cesarean delivery.
        Am J Obstet Gynecol. 2014; 210: 179-193
        • Antoine C.
        • Young B.K.
        Cesarean section one hundred years 1920-2020: the Good, the Bad and the Ugly.
        J Perinat Med. 2020; 49: 5-16