Zika activity is slowing as winter progresses, with less than a hundred new cases of pregnant women with laboratory evidence of infection reported over the 2 weeks ending Jan. 10, according to data from the Centers for Disease Control and Prevention.

The most recent CDC data show that, for the first time since early August, the majority of new cases of Zika infection among pregnant women were reported in the 50 states and the District of Columbia, compared with the U.S. territories. There were a total of 98 new cases, with 55 reported in the states and 43 in the U.S. territories.

The CDC reported weekly totals for pregnant women for most of 2016 but is now reporting every 2 weeks. The CDC noted that these are not real-time estimates. They reflect only the number of reports received, and Puerto Rico has been retroactively reporting cases for a number of months.

The total number of Zika-infected pregnant women in the United States is now 4,232 for 2016-2017. There have been 2,885 cases in the territories and 1,347 cases reported in the states/D.C. Among the cases in the states/D.C., 940 pregnancies have been completed, with Zika-related birth defects seen in 37 live-born infants and five pregnancy losses, the CDC said. The CDC is no longer reporting adverse pregnancy outcomes for the territories because Puerto Rico is not using the same inclusion criteria.

Zika cases among all Americans are still being reported weekly by the CDC, and the increase there has slowed as well: Total cases were up by 146 for the week ending Jan. 18, compared with 294 and 205 for each of the previous 2 weeks, according to CDC reports.

Zika-related birth defects reported by the CDC could include microcephaly, calcium deposits in the brain indicating possible brain damage, excess fluid in the brain cavities and surrounding the brain, absent or poorly formed brain structures, abnormal eye development, or other problems resulting from brain damage that affect nerves, muscles, and bones. The pregnancy losses encompass any miscarriage, stillbirth, and termination with evidence of birth defects.