August 1970


J. Richard Udry
    School of Public Health, University of North Carolina, Chapel Hill   27514

Abstract -- A comparison of the number of births in New York City nine months after the Great Blackout of 1965 with comparable periods for the previous five years shows no increase in births associated with the blackout.

Electric power went out in New York City and much of the Northeast in the late afternoon November 9, 1965, and stayed out for up to ten hours. On Wednesday, November 10, 1965, the New York Times carried a banner headline on page one, "POWER FAILURE SNARLS NORTHEAST; 800,000 ARE CAUGHT IN SUBWAYS HERE; AUTOS TIED UP, CITY GROPES IN DARK." Light and power first went out at 5:27 P.M. in New York City, and power in all areas was back on at 4:00 A.M.

On Wednesday, August 10, 1966, also in the Times, a page one mid-section headline announced, "BIRTHS UP 9 MONTHS AFTER THE BLACKOUT." Under the signature of Martin Tolchin, the following story appeared.

"A sharp increase in births has been reported by several large hospitals here, 9 months after the 1965 blackout.

Mount Sinai Hospital, which averages 11 births daily, had 28 births on Monday. This was a record for the hospital; its previous one-day high was 18. At Bellevue there were 29 new babies in the nursery yesterday, compared with 11 a week ago and an average of 20.

Columbia Presbyterian averages 11 births daily and had 15 Monday; St. Vincent's averages 7 and had 10; Brookdale averages 10 and had 13; and Coney Island averages 5 and had 8. However, New York and Brooklyn Jewish hospitals reported that their number of births was normal . . .

There were 16 babies at Mount Sinai yesterday, 13 at Columbia Presbyterian, and 10 at St. Vincent's, all above average. The number of births was reported normal in Nassau and Suffolk counties, many of whose commuters were stranded in the city November 9, in Newark and Jersey City which were not affected, and in hospitals in Albany, Rochester, New Haven and Providence, where the lights went on in mid-evening."

Sociologists and obstetricians were requested to comment on the reported event. One sociologist was quoted as saying, "The lights went out and people were left to interact with each other." Others said that the disruption in routine caused by the blackout and the absence of television might have contributed to the phenomenon. Christopher Tietze was more cautious in his opinion: "I am skeptical until I see the data from the entire city. There can be daily fluctuations in individual hospitals that can be misleading. If it should be true, I would think it is because people may have had trouble finding their accustomed contraceptives, or just because it was dark."

The effect of the blackout on birth rates is a relatively easy matter to determine. Through the cooperation of Carl Erhardt and the New York City Health Department, I obtained the number of births for each calendar day for the years 1961 through 1966. I took November 10, 1965, as the date of conception for the blackout babies, and assumed that the average gestational length was 280 days, counting from the last menstrual period, and therefore about 267 or 266 days from conception. Using a distribution of gestational ages at birth derived from vital statistics (Vital Statistics of the U.S., 1965), it was estimated that more than 90 percent of the births conceived on November 10th would have been born between June 27 and August 14. I reasoned that if there were an unusual number of conceptions on November 10th, then the period between June 27 and August 14, 1966, would contain a greater percentage of the year's births than that contained by the same period in other years. Table 1 presents the percentage of the year's births occurring per week from June 27 to August 14 for the years 1961 through 1966. It can be seen that 1966 is not an unusual year in this comparison. For those who still imagine that all babies conceived on a given date are also born on an exact date 267 days later, Table 1 also presents the number of births and proportion of the year's births born on that date corresponding to 267 days after the blackout, also for the years 1961 throught 1966. This number of births is not at all remarkable for 1966 when compared to the previous five years.

Table 1: Births occurring in New York City from June 29 to August 16 (except 1964 when it was June 28 to August 15) during the years 1961-1966.
Year Mean births per day Mean births per week % of year's total births # of births on 267th day

For no week is the 1966 value significantly above average for the previous five years. We therefore cannot conclude from the data presented here that the great blackout of 1965 produced any significant increase (or decrease) in the number of conceptions.

Let us not imagine that a simple statistical analysis such as this will lay to rest the myth of blackout babies. Nine months after the Great Snow of 1967 in Chicago, hospitals reported that they were preparing their facilities for an avalanche of "snow babies." It is evidently pleasing to many people to fantasy that when people are trapped by some immobilizing event which deprives them of their usual activities, most will turn to copulation.