Risk of preterm birth higher in women having kidney dysfunction before pregnancy: CMAJ
Canada: Women with kidney dysfunction before pregnancy are at increased risk of preterm birth, according to a recent study in the Canadian Medical Association Journal (CMAJ). The findings stress the need for serum creatinine (a relatively inexpensive blood test) measurement to be a part of the assessment of risk for preterm birth among those planning pregnancy.
Prepregnancy elevated serum creatinine levels (indicative of kidney dysfunction) is known to be associated with preterm birth -- a leading cause of neonatal morbidity and mortality. However, the relation is not well understood. Ziv Harel, Division of Nephrology (Garg), Western University, London, Ont., and colleagues determined the risk of preterm birth in women with prepregnancy kidney dysfunction, defined using pregnancy-specific serum creatinine cut points.
The population-based cohort study conducted in Ontario, Canada involved women aged 16 to 50 years. Thye had a singleton birth between 2006 and 2016 and measurement of serum creatinine within 10 weeks preceding their estimated conception date. The exposure was abnormally elevated prepregnancy serum creatinine, defined as greater than the 95th percentile (> 77 μmol/L), a value derived from a population-based sample of women without known kidney disease who became pregnant soon after the measurement was obtained.
The main outcome was any preterm birth from 23 to 36 weeks' gestation.
Key findings of the study include:
- Among 55 946 pregnancies, preterm birth before 37 weeks' gestation occurred in 3956 women (7.1%).
- The risk of preterm birth before 37 weeks was higher among women with prepregnancy creatinine above the 95th percentile, relative to those with prepregnancy creatinine at or below the 95th percentile (9.1% v. 7.0%; adjusted relative risk [RR] 1.23).
- The effect was significant for provider-initiated preterm birth (adjusted RR 1.30) but not for spontaneous preterm birth (adjusted RR 1.12).
"Given that prepregnancy kidney dysfunction conferred an increased risk of preterm birth, measurement of serum creatinine (a relatively inexpensive blood test) may form part of the assessment of risk for preterm birth among those planning pregnancy," concluded the authors.
The study, "Prepregnancy renal function and risk of preterm birth and related outcomes," is published in the Canadian Medical Association Journal.