Association between timing and duration of breech presentation during pregnancy and developmental dysplasia of the hip: A case-control study.
Annemieke Konijnendijk, Ellen Vrugteveen, Brenda Voorthuis and 1 others
PMID 34472998WHAT IT FOUND
Term children whose breech position was recorded from 37.0 weeks to birth had a more than three times higher risk of developmental dysplasia of the hip.
Earlier breech alone did not raise risk, and longer breech exposure raised risk further.
Key findings
01In term children, breech presentation from 37.0 weeks to birth had an adjusted odds ratio of 3.33 for DDH compared with no breech or breech only before 37.0 weeks.
02Breech presentation only in gestational period 30.0 to 36.6 weeks did not increase the risk of DDH.
03The risk of DDH increased with longer breech duration: 5 to 8 weeks OR 2.65 and 9 to 13 weeks OR 3.63.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Controls were recruited by convenience sampling. The control group had 21 (12.0%) term breech children in the last week of pregnancy, higher than the reported four to five percent. This means the true association may be higher than reported. Many parents did not have a pregnancy card and reported presentation from memory. This applied to 89 case parents and 127 control parents. One or more pregnancy presentations were unknown for 30 cases and 38 controls. Missing data were imputed. Cases were recruited through a patient association and may represent more severe DDH. Breech timing analyses included only term children, so the findings do not address preterm infants who present breech. The sample was relatively small and some subcategories were low.
The easy way to misread this
Do not conclude that breech presentation at any point after 30.0 weeks equally raises DDH risk. Only breech recorded from 37.0 weeks onward had a more than three times higher adjusted risk, and the study relied on parental recall and convenience controls.