A randomized controlled trial on the effects of periconceptional and prenatal folic acid supplementation on congenital anomalies and preterm birth

Approximately one in 44 babies is affected with a congenital anomaly (CA) in
Europe (1). About 10% of these CA affect the nervous system (1). The beneficial
effects of periconceptional folic acid (FA, vitamin B11) supplementation on
neural tube defects (NTD) are evident from randomised controlled trials (RCTs)
in high and low risk populations (2;3).

Risk factors for congenital anomalies

Some (groups of) women have a higher risk for having a baby with a congenital
anomaly. Mothers of previous children with NTDs have an increased risk of
having another child with an NTD. In the Netherlands, these women are
prescribed a higher dose of FA (4.0 mg) periconceptional and during the first
trimester of pregnancy (3).
Besides genetic predisposition, some gene-environment interactions are known.
An example is the interaction between the maternal MTHFR 677C>T polymorphism
and FA. Mothers with MTHFR 677TT genotype (homozygous for the polymorphism) who
did not use folate supplementation periconceptionally, have a twofold increased
risk of having a child with a congenital heart defect (4).

The effects of folic acid

The beneficial effects of periconceptional folic acid (FA) supplementation on
neural tube defects (NTD) are evident. Numerous studies have shown that FA
supplementation reduces the risk of NTD considerably (5;6). Internationally, a
dose of 0.4 mg FA periconceptionally has been agreed upon as the recommended
dose (7). But although 0.4 mg is recommended, there is still great uncertainty
about the optimal dose of FA supplementation. Wald et al (8) studied the
dose-response relationship in a large study, and showed that with higher doses
of FA supplementation, more NTDs were prevented. They concluded that the
current recommended daily dose of FA will render only partial protection
against NTDs. According to Wald et al*s analysis, 5 mg of FA would be necessary
to render 90% protection within the populations.

In addition to these larger effects in the prevention of NTD with a higher
dose, FA very probably also has a preventive effect on the birth prevalence of
congenital anomalies other than NTD. Case-control studies have yielded strong
evidence for a preventive effect on the prevalence of congenital heart defects
(9), and reasonable evidence exists for a preventive effect on limb defects and
urinary tract malformations (11;12). One case-control study showed a possible
effect on Down syndrome (13). Ambiguous results were found with regards to the
prevention of clefts (10). All effects on congenital anomalies are achieved by
FA supplementation before conception and in the first trimester of pregnancy.
Another effect of FA supplementation during pregnancy, with a probably
completely independent causal pathway, is the effect on preeclampsia and on
preterm birth. From case-control studies, strong evidence is found that FA
supplementation (dosages from 0.4 mg to 3.0 mg or more) in the 2nd and/or 3rd
trimester, reduces the risk of preeclampsia and preterm birth (14-16).
However the level of that evidence is insufficient to draw final conclusions.
An RCT is needed to assess whether e.g. 0.8 mg of FA supplementation in 2nd and
3rd trimester has a protective effect on preterm birth compared with the
current Recommended Daily Average of 0.4 mg Food Folate Equivalents (FFE), (17)
for which only a 0.1 to 0.2 mg FA supplementation would be needed.

Studies on folic acid antagonists show similar effects on congenital anomalies.
The use of these kinds of medication during the first trimester of pregnancy is
associated with an increased risk for congenital anomalies such as NTDs,
urinary tract defects and cardiovascular defects (18-20), but not with
pregnancy complications such as preterm delivery perinatal mortality, low birth
weight and low Apgar scores (20).
Side-effects of folic acid

The safety of (high doses of) FA supplementation has been topic of debate.
Concerns were mostly that FA supplementation would mask pernicious anaemia due
to B12 deficiency and would increase the risk of cancer. Several studies were
unable to detect the effect of masking pernicious anaemia (21). Furthermore, FA
might be related to the risk of certain cancers, as shown by Ebbing et al (22),
although other population-based studies have shown FA-use to be associated with
a decline in cancer incidence (21). It might be that FA increases the risk of
cancer for individuals with a history of or predisposition to cancer, or
influenced growth of cancers that were silent. However, this is likely only the
result of long-term exposure, and not when only using FA supplementation for
less than a year around conception and during pregnancy. Recently the UK food
agency reaffirmed its advice for compulsory fortification based on the latest
evidence from published and not yet published studies (23). Other concerns stem
from a possible relation between childhood asthma and FA consumption during
pregnancy (24). The strength of the evidence is however not such, that this has
implications on recommendations of FA consumption during pregnancy at this
time. However, it is important to critically follow all new evidence on this
(and other topics) as well.

Because of a very low response rate, and termination of funding of the project,
recruitment of participants stopped November 1st, 2013. Women who were pregnant
before that date will be followed up, until a year after giving birth, in order
to obtain data about pregnancy and birth outcome, and the presence of
congenital anomalies. This follow up will be approximately till June 2015.

In the proposed study, two main issues will be addressed: first, it will be
studied whether a high dose (4.0 mg) of FA supplementation periconceptional has
an added value over the now recommended low dose of 0.4 mg in the prevention of
congenital anomalies (CA). Such a study requires a very large number of
participants in order to have sufficient power to detect differences. It is
virtually impossible to recruit this number of participants in one country, and
therefore several international studies will be combined. The lead for this
combined study is the International Clearinghouse for Birth Defects
Surveillance and Research in Italy, where a FA supplementation trial is
currently being conducted. Each of the two trials aims at recruiting 5000
women. A total of 10.000 women is sufficient to assess differences in
congenital anomalies. Hopefully, more countries can and will participate in
these combined analyses, so that differences in specific congenital anomalies
can be detected as well.
The second main issue that will be addressed in the proposed study is whether
0.8 mg FA supplementation in later pregnancy (2nd and 3rd trimester), compared
to 0.2 mg FA (RDA), has a preventive effect on preeclampsia and preterm birth.

Research questions:
1. What is the effect of a high (4.0 mg) versus low (0.4 mg) dose of folic acid
supplementation from 4 weeks before conception to 12 weeks of gestation on the
prevalence of folic acid related congenital anomalies?
2. What is the effect of 0.8 mg folic acid supplementation versus 0,2 folic
acid supplementation from 12 weeks of gestation to the end of pregnancy on the
prevalence of preterm birth and preeclampsia?

Secondary research questions:
3. Which side effects of periconceptional and prenatal folic acid use are
reported by trail participants?
4. What associations between study groups and the incidence, severity and types
of side effects reported, can be identified?
a. During the first period (until 12 weeks of gestation);
b. During the second period (from 12 weeks of gestation until the end of the
pregnancy).

The Dutch study will be designed as a randomised controlled trial, with four
intervention arms:
1) low dose (0.4 mg) of FA from 4 weeks preconception to 12 weeks of gestation,
and RDA (0,2 mg) FA supplementation after 12 weeks of gestation;
2) low dose (0.4 mg) of FA from 4 weeks preconception to 12 weeks of gestation,
and 0.8 mg FA supplementation after 12 weeks of gestation;
3) high dose (4.0 mg) of FA from 4 weeks preconception to 12 weeks of
gestation, and RDA (0,2) mg FA supplementation after 12 weeks of gestation;
4) high dose (4.0 mg) of FA from 4 weeks preconception to 12 weeks of
gestation, and 0.8 mg FA supplementation after 12 weeks of gestation.

Randomisation is double blind: participants, pharmacists and researchers are
blind for the doses. Independent researchers of MediClara, AHZ and VUmc
datamanagement have the randomisation code.

Women in all intervention groups will receive identical pills, containing two
different doses of folic acid (0.4 or 4.0 mg). Women will start taking the
pills after randomisation, but at least 4 weeks before conception, and will
receive new pills from their pharmacy every 16 weeks.
At 12 weeks of gestation, all women will receive a new set of pills, half of
them will receive 0.2 mg supplements and half will receive 0.8 mg of FA.

Follow-up:
After randomisation, women will receive new pills every 16 weeks at the
pharmacy, until a period of 12 months has gone by without them getting pregnant
or until the end of their pregnancy (live birth, stillbirth, spontaneous
abortion, or termination).

Intervention

Participants have to take one pill each day, starting at least one month before
conception, until the end of pregnancy. This is largely consistent with the
current advice given to women in the Netherlands who want to become pregnant or
are pregnant. The difference between the current advice and the study
intervention is in the duration of the usage of FA supplementation pills,
respectively until 12 weeks of gestation and until the end of pregnancy.
However, many pregnant women choose to use multivitamin supplements during the
whole pregnancy period and even afterwards, during breast feeding period.
Therefore, for most participants participation will not differ much from their
normal behaviour.

Measurements

Most measurements will be completed without involvement of the participant.
These data will be retrieved from medical records and EUROCAT after consent.
Additional information will be retrieved from small questionnaires, which can
take several minutes to fill in, for example when picking up the pills at the
CP.
It is possible that the GP, gynaecologist, midwife or other involved medical
specialists take additional measurements which would not always be completed in
usual care (but are optional in usual care), to make sure the medical records
are sufficient for this study. These possible additional measures will not
include invasive measurements.

Benefits

There are no direct health benefits for the participants. However, FA is shown
to be effective in the prevention of NTDs, so participants profit from this
risk reduction (6;48).
Additionally, FA supplements are administered for free to participants,
therefore there is a financial benefit to those who would have used FA
supplements on their own initiatives when not in the study.

Risks
With a high dose of 5.0 mg FA, some hypersensitivity reactions (rash, fever)
have been reported, but these occur rarely.