Haemoglobin trajectories during pregnancy and associated outcomes using pooled maternity and hospitalization data from two tertiary hospitals.
BACKGROUND AND OBJECTIVES
This study aimed to describe how haemoglobin trajectories in pregnant Australian women were associated with subsequent postpartum haemorrhage, blood transfusion and other outcomes.


MATERIALS AND METHODS
The study was conducted in two tertiary public hospitals in Australia, using routinely collected maternity and hospital data on singleton pregnancies (2011-2015). Latent class growth modelling defined trajectories among those with at least one haemoglobin in each of three antenatal time periods (0-15, 16-30 and 31+ weeks; n = 7104). Observed over expected ratios were calculated after predicting expected outcomes with adjusted logistic regression.


RESULTS
The mean minimum haemoglobin levels across the three periods were 127·9, 116·5 and 119·3 g/l. We identified seven groups of women with similar haemoglobin trajectories: five with parallel U-shaped trajectories, one with increasing and one with decreasing trajectory. Thirty-eight women (0.5%) had very low haemoglobin across the pregnancy and the highest adverse outcomes, including higher than expected blood transfusion risk. One hundred thirteen women (1.6%) with a progressively decreasing trajectory also had higher risk of transfusion. Women with high haemoglobin across the antenatal period had higher than expected risk of preterm birth, small for gestational age and infants transferred to higher care.


CONCLUSIONS
Haemoglobin trajectories across pregnancy can predict women at higher risk of requiring transfusion around birth. Women who maintain high haemoglobins across the pregnancy are worthy of increased surveillance as they carry increased risks of newborn morbidity.
['Randall|Deborah A|DA|https://orcid.org/0000-0002-5075-0227', 'Patterson|Jillian A|JA|https://orcid.org/0000-0002-9888-9818', 'Gallimore|Felicity|F|', 'Morris|Jonathan M|JM|', 'Simpson|Judy M|JM|', 'McGee|Therese M|TM|', 'Ford|Jane B|JB|', '|||']
D000328:Adult D001315:Australia D001803:Blood Transfusion D005260:Female D006454:Hemoglobins D006760:Hospitalization D006801:Humans D007231:Infant, Newborn D009017:Morbidity D006473:Postpartum Hemorrhage D011247:Pregnancy D011256:Pregnancy Outcome D062606:Tertiary Care Centers
haemoglobins pregnancy postpartum haemorrhage blood transfusion prenatal care