Intra-Abdominal Pressure Measurements in Term Pregnancy and Postpartum: An Observational Study

Objective To determine intra-abdominal pressure (IAP) and to evaluate the reproducibility of IAP-measurements using the Foley Manometer Low Volume (FMLV) in term uncomplicated pregnancies before and after caesarean section (CS), relative to two different reference points and to non-pregnant values. Design Observational cohort study. Setting Secondary level referral center for feto-maternal medicine. Population Term uncomplicated pregnant women as the case-group and non-pregnant patients undergoing a laparoscopic assisted vaginal hysterectomy (LAVH) as control group. Methods IAP was measured in 23 term pregnant patients, before and after CS and in 27 women immediately after and 1 day after LAVH. The midaxillary line was used as zero-reference (IAP MAL ) in all patients and in 13 CS and 13 LAVH patients, the symphysis pubis (IAP SP ) was evaluated as additional zero-reference. Intraobserver correlation (ICC) was calculated for each zero-reference. Paired student's t -tests were performed to compare IAP values and Pearson's correlation was used to assess correlations between IAP and gestational variables. Main outcome measures ICC before and after surgery, IAP before and after CS, IAP after CS and LAVH. Results The ICC for IAP MAL before CS was lower than after (0.71 versus 0.87). Both mean IAP MAL and IAP SP were significantly higher before CS than after: 14.0±2.6 mmHg versus 9.8±3.0 mmHg (p<0.0001) and 8.2±2.5 mmHg versus 3.5±1.9 mmHg (p = 0.010), respectively. After CS, IAP was not different from values measured in the LAVH-group. Conclusion IAP-measurements using FMLV is reproducible in pregnant women. Before CS, IAP is increased in the range of intra-abdominal hypertension for non-pregnant individuals. IAP significantly decreases to normal values after delivery.