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Effects of restricted caffeine intake by mother on fetal, neonatal and pregnancy outcome

  1. Shayesteh Jahanfar1,*,
  2. Sharifah Halimah Jaafar2

Editorial Group: Cochrane Pregnancy and Childbirth Group

Published Online: 28 FEB 2013

Assessed as up-to-date: 29 NOV 2012

DOI: 10.1002/14651858.CD006965.pub3


How to Cite

Jahanfar S, Jaafar SH. Effects of restricted caffeine intake by mother on fetal, neonatal and pregnancy outcome. Cochrane Database of Systematic Reviews 2013, Issue 2. Art. No.: CD006965. DOI: 10.1002/14651858.CD006965.pub3.

Author Information

  1. 1

    University of British Columbia, School of Population and Public Health, Vancouver, British Colombia, Canada

  2. 2

    Ipoh Specialist Hospital, Department of Obstetrics and Gynaecology, Ipoh, Perak, Malaysia

*Shayesteh Jahanfar, School of Population and Public Health, University of British Columbia, 2206 East Mall, Vancouver, British Colombia, VT6 1Z3, Canada. jahanfar2000@yahoo.com. shayeste@interchange.ubc.ca.

Publication History

  1. Publication Status: New search for studies and content updated (no change to conclusions)
  2. Published Online: 28 FEB 2013

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This is not the most recent version of the article. View current version (09 JUN 2015)

 
Characteristics of included studies [ordered by study ID]
Bech 2007

MethodsRandomised: method of randomisation is mentioned as central computer randomisation.

Double blind: yes. It was mentioned that participants and study co-ordinator were both blinded. Data analyst was also blinded until end of data analysis.

Follow-up is described: done on weeks 20, 25, 32 and 4 weeks after expected delivery. 8.6% of participants in decaffeinated group and 4.9% of participants in the caffeinated group dropped out before giving birth.


ParticipantsOverall 1207 pregnant women were randomised. 10 participants were excluded (due to erroneous serial number, participating twice and second pregnancy); 568 women were randomised to caffeinated instant coffee and 629 to decaffeinated instant coffee. Then, a total of 1153 women with a live born singleton were included in the analysis of birthweight and length of gestation. Of these, 8.60% (54/629) randomised to the decaffeinated group and 4.90% (28/568) randomised to the caffeinated group dropped out of the study before giving birth. 

Inclusion criteria: Danish-speaking women at less than 20 weeks' gestation who drank 3 cups of coffee per day.

Those with history of low birthweight baby (< 2500 g), preterm deliveries, kidney disease, epilepsy, diabetes, or metabolic disorders were excluded from the study.


InterventionsTaking 3 cups of decaffeinated instant coffee (an average of 62 mg/day) versus the same quantity of caffeinated instant coffee.


OutcomesMean birthweight and length of gestational age were considered as the main outcomes. Length, head circumference, abdominal circumference, placenta weight, and Apgar score were secondary outcomes; these are not referenced in this review as they did not fit our objective.


NotesThis study was done between April 1996 and April 1998 in the Department of Obstetrics, Aarhus University Hospital, Denmark.


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low riskWomen randomised to receive decaffeinated or caffeinated coffee.

Allocation concealment (selection bias)Low riskCompleted using computerised randomisation.

Blinding of participants and personnel (performance bias)
All outcomes
Low riskProject co-ordinator and participants were blinded to the type of coffee.

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskNot reported.

Incomplete outcome data (attrition bias)
All outcomes
Low riskOnly 8.60% (54/629) participants from the decaffeinated group and 4.90% (28/568) from the caffeinated group dropped out of the study.

Selective reporting (reporting bias)Unclear riskNot clear.

Other biasUnclear riskThere are many other sources of dietary caffeine (tea, chocolate, etc) which were not measured in the study.  Women in the decaffeinated coffee group could have increased their caffeine intake from other sources.

Robinson 2009

MethodsDescribed as a "double-blind, randomized, cross-over study" - but methods not clearly described. No details regarding the cross-over. Women with negative GDM test were assigned to control group (n=19) and women with an initial positive GDM screen were assigned to the experimental group (n=8). Within the control and the GDM group, women underwent two further fastings at approximately 28 to 29 weeks and 29 to 30 weeks' gestation (one week apart). Treatments were randomized, and investigators and study participants were blinded to the order of the treatments.


ParticipantsPregnant women were referred to obstetric clinics between 24-28 weeks of gestation and underwent GDM testing for screening.


InterventionsFollowing an overnight fasting, women ingested caffeine (3 mg/kg pre-pregnancy body weight) with 250 mL of water, equivalent of 1-2 cups of coffee) or an identical-appearing placebo (gelatin) capsule with the same amount of water.


OutcomesOne hour after caffeine or gelatin intake a 75 g 2-hour oral glucose tolerance test was taken. Inslun, C-Peptide, proinsulin, free fatty acids, epinephrine and methylxanthines were also measured.


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Unclear riskWomen were randomised to receive caffeine or gelatin capsule. No details of method for sequence generation.

Allocation concealment (selection bias)Unclear riskThose who had an initial 50 g glucose screen (1-hour glucose value < 7.8 mmol/L) were assigned to the control group. Women with an initial positive 50 g glucose screen were assigned to GDM group if they also had two or more glucose values greater than 5.3 mmol/L (fasting), 10.6 mmol/L (1h), or 8.9 mmol/L (2h) on a subsequent 75 g fasting OGTT. A 1-hour glucose value of > 10.3 mmol/L after a 50 g glucose was also considered diagnostic for GDM.

Within the control group and the GDM group, women underwent two further 75 g fasting OGTTs at approximately 28 to 29 and 29 to 30 weeks' gestation (i.e., one week apart).

No information regarding allocation concealment.

Blinding of participants and personnel (performance bias)
All outcomes
Low riskInvestigators and study participants were blinded to the order of treatment.

Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskNot reported.

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskAttrition is not mentioned.

Selective reporting (reporting bias)Low riskReporting bias is unlikely.

Other biasUnclear riskDescribed as "double-blind, randomized, cross-over study" - but methods not clearly described. No description of the cross-over.

 
Comparison 1. Caffeinated (experimental group) versus decaffeinated group (control group)

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Mean birthweight (grams)11197Mean Difference (IV, Fixed, 95% CI)20.00 [-48.68, 88.68]

 2 Frequency of preterm birth11153Risk Ratio (M-H, Fixed, 95% CI)0.81 [0.48, 1.37]

 3 Small-for-gestational age11150Risk Ratio (M-H, Fixed, 95% CI)0.97 [0.57, 1.64]

 4 Serum Insulin (pmol/L) (not prespecified)127Mean Difference (IV, Fixed, 95% CI)38.8 [13.57, 64.03]