Treatment effects by subgroups according to the time from the start of treatment until birth.

<p>Treatment effects by subgroups according to the time from the start of treatment until birth.</p

Treatment effects among the subgroups considered by the purpose of the treatment.

<p>Treatment effects among the subgroups considered by the purpose of the treatment.</p

Treatment effects by the individual reasons why the pregnancy was considered to be high risk.

<p>Treatment effects by the individual reasons why the pregnancy was considered to be high risk.</p

Treatment effects among the subgroups considered by dose actually received.

<p>Treatment effects among the subgroups considered by dose actually received.</p

Treatment effects among the subgroups considered by multiple birth.

<p>Treatment effects among the subgroups considered by multiple birth.</p

Preferred Reporting Items for Systematic Review and Meta-analyses of Individual Participant Data (PRISMA-IPD) flow diagram.

<p>Abbreviations: CP, cerebral palsy.</p

Maternal secondary outcomes^*.

<p>Maternal secondary outcomes^{<a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.1002398#t008fn002" target="_blank">*</a>}.</p

Death or cerebral palsy^* (all trials).

<p>Death or cerebral palsy^{<a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.1002398#t003fn002" target="_blank">*</a>} (all trials).</p

Included studies and their characteristics.

<p>Included studies and their characteristics.</p

Treatment effects among the subgroups considered by whether maintenance therapy was received or not.

<p>Treatment effects among the subgroups considered by whether maintenance therapy was received or not.</p