Maternal heart rate during the first 48 h postpartum: a retrospective cross sectional study

Abstract

Throughout pregnancy and the puerperium significant cardiovascular changes occur. Maternal heart 70 rate increases by approximately 20% from the pre-conception baseline to the third trimester of 71 pregnancy (1, 2), with a further increase during labour (3). Whilst these changes are well 72 understood, the changes in the postpartum period are less well defined. Studies show maternal 73 heart rate returns to baseline weeks to months post-delivery (4-7), yet the early postpartum period 74 remains poorly described. Knowledge of what constitutes normal during this period is clinically 75 pertinent to facilitate identification of sick women, and avoid inappropriate investigation of healthy 76 women. In some cases the cause of postpartum tachycardia is evident (haemorrhage, sepsis) (8)(9)(10)(11)(12). 77In other cases it is less obvious and should prompt further investigation for causes such as occult 78 bleeding, cardiac pathology or pulmonary embolism (3,(13)(14)(15). 79Modified Early Obstetric Warning Scores (MEOWS) are widely used. The parameters used vary (16, 80 17) and have often been developed from a non-pregnant population. Data derived from a 81 postpartum population would improve the pre-existing MEOWS scores validity; providing a platform 82 for further investigation into the relationship between postpartum heart rate and negative 83 outcomes and ultimately the creation of a postpartum specific clinical assessment tool. 84Study Aims 85 1. Describe the distribution of heart rate in the first 48 hours postpartum (at 6, 12, 24 and 48 86 hours post-delivery), in women with no evidence of sepsis, haemorrhage or anaemia. 87 2. Investigate the relationship between postpartum heart rate and other maternal factors 88(maternal BMI at booking, maternal age, method of delivery, puerperal blood loss, discharge 89 haemoglobin and length of hospital stay). 90 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 3 Gynaecologists' guidelines for major postpartum haemorrhage (19)) or whose discharge 111 haemoglobin was < 100 g/l (British Society of Haematology guidelines on maternal and postpartum 112 anaemia (20)). 113 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 4 Materials and Methods 91 Study Design Statistical Analyses 114Statistical analyses were performed using IBM® SPSS® Statistics 22 (The International Business 115 Machines Corporation®, New York, NY, USA). 116Central tendency for heart rate at each time period postpartum (6, 12, 24 and 48 hours) was 117 calculated using the mea μ . Spread as calculated usi g standard deviation (SD) and suggested 118 normal range upper thresholds were calculated using the me...

Shock index and vital-sign reference ranges during the immediate postpartum period

“…As in the present study, a greater mean heart rate was recorded among patients who underwent a cesarean delivery compared with patients who underwent non‐instrumental vaginal deliveries beyond 6 hours following delivery. Further, this study reported a similar 95th percentile heart rate value at 24 hours postpartum (112 bpm) compared to the present study (110 bpm). Among non‐obstetric populations, a heart rate of above 120 bpm has been recorded as a criterion for class 3 hemorrhage, the stage where decompensation occurs and aggressive resuscitation is needed .…”

“…To the best of our knowledge, ROPE reference values have not been reported previously among patients during the postpartum period; however, higher values in comparison with a non‐obstetric population were expected for reasons similar to those for the increases in the shock index. A recent cross sectional study reported reference values for maternal heart rate during the first 48 hours following delivery. As in the present study, a greater mean heart rate was recorded among patients who underwent a cesarean delivery compared with patients who underwent non‐instrumental vaginal deliveries beyond 6 hours following delivery.…”

“…Taylor ET al. sectional study 7 reported reference values for maternal heart rate during the first 48 hours following delivery. As in the present study, a greater mean heart rate was recorded among patients who underwent a cesarean delivery compared with patients who underwent non-instrumental vaginal deliveries beyond 6 hours following delivery.…”

Management of palpitations and cardiac arrhythmias in pregnancy

“…One study found the upper threshold of normal to be around 110 beats per minute within the first 48 hours postpartum. 8 left axis deviation, within the normal range, in part due to the rotation of the heart from the gravid uterus. 5 Inverted or flattened T waves in leads III, V1-V3 and a Q wave in leads II, III and aVF, are also commonly seen.…”

“…Postpartum, changes in heart rate are less well defined. One study found the upper threshold of normal to be around 110 beats per minute within the first 48 hours postpartum …”