[Use of antibiotics during pregnancy]

Use of interrupted time-series analysis to characterise antibiotic prescription fills across pregnancy: a Norwegian nationwide cohort study

OBJECTIVES

Antibiotics are the most frequently prescribed medications for pregnant and breastfeeding women. We applied interrupted time-series analysis (ITSA) to describe antibiotic prescription fills patterns in pregnant women and examined recurrent antibiotic fills in subsequent pregnancies.

DESIGNS

A population-based drug utilisation study.

SETTING

Norwegian primary care.

PARTICIPANTS

653 058 pregnancies derived from Medical Birth Registry of Norway linked to the Norwegian Prescription Database (2006-2016).

MAIN OUTCOME MEASURE

Proportion of pregnancies exposed to antibiotics aggregated by week in pregnancy time windows.

STATISTICAL ANALYSES

We descriptively analysed antibiotic prescription fills patterns and components in pregnant women. The changes in antibiotic fills in pregnancy time windows were assessed using ITSA. Interruptions points at week 4 to week 7 into pregnancy and delivery were used. Factors associated with antibiotic fills during pregnancy were identified using generalised estimating equations for Poisson regression. Recurrent antibiotic use was estimated using proportion of women who filled antibiotic prescription in a subsequent pregnancy.

RESULTS

Antibiotics were filled in 27.6% pregnancies. The ITSA detected an immediate decrease of 0.07 percentage points (95% CI -0.13 to -0.01) in the proportion of exposed pregnancies at 4 weeks after conception, mainly among women taking folic acid before pregnancy. This proportion increased shortly after delivery (immediate change=1.61 percentage points (95% CI 0.31 to 2.91)) then decreased gradually afterwards (change in slope=-0.19 percentage points, 95% CI -0.34 to -0.05)). The strongest factor associated with antibiotic fills during pregnancy was having recurrent urinary tract infections (adjusted OR=2.65, 95% CI 2.59 to 2.72). Women who had filled antibiotics during a pregnancy were up to three times more likely to fill antibiotics in the subsequent pregnancies.

CONCLUSIONS

ITSA highlighted important impact of pregnancy and delivery on antibiotic fillings. Having antibiotic fills in a pregnancy was associated with recurrent antibiotic fills in subsequent ones.

Antibiotic-Related Adverse Drug Reactions in Patients Treated on the Dermatology Ward of Medical University of Gdańsk

Adverse drug reactions (ADRs) are unexpected reactions to a medication administered in a correct way at a standard dose. Drug-induced skin reactions account for 60-70% of all ADRs. The aim of the study is to determine the prevalence of antibiotic-related dermatological ADR in patients treated in the department of Dermatology, Venerology and Allergology of the University Clinical Center in Gdańsk, Poland, in the years 2004-2021. A retrospective analysis of patients' medical files was conducted in order to identify cases of ADR connected with the use of antibiotics, yielding 84 cases. The most common group of antibiotics were β-lactam, causing ADR in 47 patients. β-lactam antibiotics in our study included amoxicillin, alone and combined with clavulanic acid, and cephalosporins, affecting 22, 18 and 7 patients, respectively. In conclusion, β-lactam antibiotics showed the highest prevalence among antibiotic-induced skin reactions. They accounted for 15% of cases of all dermatological drug reactions and 55% of those caused by antibiotics. Especially amoxicillin, prescribed as a single drug or in combination with clavulanic acid, was commonly the culprit. Due to its wide use in the hospital and outpatient clinic, these adverse reactions have to be kept in mind by both hospital staff and general practitioners.

Fertility treatment and oral contraceptive discontinuation for identification of pregnancy planning in routinely collected health data - an application to analgesic and antibiotic utilisation

BACKGROUND

Women with unplanned pregnancies use folic acid less frequently, and more often use potentially teratogenic medications in the first trimester. Yet most studies based on routinely collected data lack information on pregnancy planning. Further, only pregnancies proceeding beyond a certain gestational age appear in routinely collected data, creating the possibility for collider-stratification bias. If pregnancy intention could be identified, pregnancies could be ascertained earlier. This study aimed to investigate fertility treatment and discontinuation of oral contraception (OC) as proxies for pregnancy planning by describing variations in patterns of prescription fills for antibiotics and analgesics during the peri-pregnancy period by these proxies of pregnancy intention.

METHODS

Fertility treatment with clomiphene and discontinuation of OC were identified in the Norwegian Prescription Database (NorPD) and linked with data from the Medical Birth Registry of Norway for the years 2006 to 2017. Filled prescriptions for antibiotics and analgesics from NorPD were displayed for women on fertility treatment, women who discontinued OC before pregnancy, and women who discontinued during pregnancy.

RESULTS

Of 172,585 included pregnancies, fertility treatment was identified in 19,449, and OC discontinuation before or during pregnancy in 153,136. Women who discontinued OC during pregnancy were less likely to use preconception folic acid (25.4%) than women who discontinued before pregnancy (32.9%), and women on fertility treatment (51.0%). Proportions of first trimester prescription fills were 4.9% (analgesics) and 12.8% (antibiotics) for women who discontinued OC during pregnancy, compared to 4.0 and 11.4% in women who discontinued OC before pregnancy, and 4.7 and 11.0% in women on fertility treatment.

CONCLUSIONS

There were no substantial differences in patterns of prescription fills for analgesics and antibiotics before or during pregnancy by fertility treatment and OC discontinuation. This suggests that there were few differences in medication use between women with planned and unplanned pregnancies, or that fertility treatment and timing of OC discontinuation from routinely collected health data cannot stand alone in the identification of unplanned pregnancies. A narrower definition of OC discontinuation during pregnancy seemed to be a better proxy, but this should be confirmed in other studies.