Table of Contents

Component Description

The NHANES program suspended field operations in March 2020 due to the coronavirus disease 2019 (COVID-19) pandemic. As a result, data collection for the NHANES 2019-2020 cycle was not completed and the collected data are not nationally representative. Therefore, data collected from 2019 to March 2020 were combined with data from the NHANES 2017-2018 cycle to form a nationally representative sample of NHANES 2017-March 2020 pre-pandemic data. These data are available to the public. Please refer to the Analytic Notes section for more details on the use of the data.

The reproductive health section (variable name prefix RHQ) contains questions for females only. Questions on reproductive health include menstrual history, pregnancy history, hormone replacement therapy use, and other related reproductive conditions. A question used to calculate estimated time in months at menarche for youth 12-19 was added in 2017-2018.

Eligible Sample

Female participants aged 12 years and older in the NHANES 2017-March 2020 pre-pandemic sample were eligible. Select variables related to pregnancy and hysterectomy have been excluded from this public use data file for those aged 12-19 years and over 44 years due to disclosure risks.

Interview Setting and Mode of Administration

These questions were asked at the mobile examination center (MEC), by trained interviewers, using the Computer-Assisted Personal Interview (CAPI) system as part of the MEC interview. Both proxy interviewers and interpreters were permitted for these questions.

Quality Assurance & Quality Control

The CAPI system is programmed with built-in consistency checks to reduce data entry errors. CAPI also uses online help screens to assist interviewers in defining key terms used in the questionnaire.

Data Processing and Editing

Edits were made to ensure the completeness, consistency, and analytic usefulness of the data.

Analytic Notes

The COVID-19 pandemic required suspension of NHANES 2019-2020 field operations in March 2020 after data were collected in 18 of the 30 survey locations in the 2019-2020 sample. Because the collected data from 18 locations were not nationally representative, these data were combined with data from the previous cycle (2017-2018) to create a 2017-March 2020 pre-pandemic data file. A special weighting process was applied to the 2017-March 2020 pre-pandemic data file. The examination sample weights in the demographic data file should be used to calculate estimates from the combined cycles. These sample weights are not appropriate for independent analyses of the 2019-2020 data and will not yield nationally representative results for either the 2017-2018 data alone or the 2019-March 2020 data alone. Please refer to the NHANES website for additional information for the NHANES 2017-March 2020 pre-pandemic data, and for the previous 2017-2018 public use data file with specific weights for that 2-year cycle.

This data file contains complete records for variables related to pregnancy only for females aged 20-44 years. The complete data file containing all variables for females 12 years and older (P_RHQ _R) is available through the NCHS Research Data Center.

In this combined special data file, only variables contained in both cycles 2017-2018 and 2019-March 2020 were included. Question inclusion, wording, target ages and skip patterns have changed periodically since RHQ 1999-2000. It is recommended that analysts review questions, documentation, and codebooks, as well as unweighted counts, prior to analysis.

In addition, survey design changes have occurred over the cycles. In 2007, pregnant women and persons 12-19 years were no longer oversampled. Additionally, for each of the race/ethnicity domains, the former age domains 12-15 and 16-19 were combined and the age minority domain 40-59 was split into two 10-year age sampling domains: 40-49 and 50-59 years. These changes resulted in an increase in the actual number of participants aged 40-59 years and a decrease in participants aged 12-19 years, as compared to previous cycles. Therefore, unweighted frequencies of certain reproductive conditions may differ slightly in this survey cycle compared to survey cycles prior to 2007.

RHD018: estimated age in months at time of menarche was calculated from date of birth (month and year) and reported age and month at first menarche. For those who reported month of menarche in their birth month, it was not possible to discern which year of age menarche occurred. Therefore, these records were coded as “missing” responses.

RHD143: Current pregnancy status from question: “are you pregnant now?” Note that the response found here may be differ from that found in the pregnancy status variable, RIDEXPRG, in the NHANES DEMO data file.

Please refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial for further details on the use of sample weights and other analytic issues.

Codebook and Frequencies

SEQN - Respondent sequence number

Variable Name:
SEQN
SAS Label:
Respondent sequence number
English Text:
Respondent sequence number.
Target:
Females only 12 YEARS - 150 YEARS

RHQ010 - Age when first menstrual period occurred

Variable Name:
RHQ010
SAS Label:
Age when first menstrual period occurred
English Text:
The next series of questions are about {your/SP's} reproductive history. I will begin by asking about {your/SP's} periods or menstrual cycles. How old {were you/was SP} when {you/SP} had {your/her} first menstrual period?
English Instructions:
CODE "0" IF HAVEN'T STARTED YET. CAPI INSTRUCTION: SOFT EDIT VALUES: 8-25 YEARS. HARD EDIT VALUES: AGE OF 1ST PERIOD CANNOT BE GREATER THAN CURRENT AGE. ENTER AGE IN YEARS.
Target:
Females only 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
6 to 19 Range of Values 4808 4808
0 Hasn't started yet 62 4870 End of Section
20 20 years or older 8 4878
777 Refused 4 4882 RHQ020
999 Don't know 50 4932 RHQ020
. Missing 382 5314

RHD018 - Estimated age in months at menarche

Variable Name:
RHD018
SAS Label:
Estimated age in months at menarche
English Text:
Derived from RHQ018 - In what month did {you/SP} have {your/her} first menstrual period?
Target:
Females only 12 YEARS - 19 YEARS
Code or Value Value Description Count Cumulative Skip to Item
103 to 191 Range of Values 685 685
7777 Refused 0 685
9999 Don't know 47 732
. Missing 4582 5314

RHQ020 - Age range at first menstrual period

Variable Name:
RHQ020
SAS Label:
Age range at first menstrual period
English Text:
{Were you/Was SP}...
Target:
Females only 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Younger than 10 1 1
2 10 to 12 12 13
3 13 to 15 17 30
4 16 or older 10 40
7 Refused 1 41
9 Don't know 9 50
. Missing 5264 5314

RHQ031 - Had regular periods in past 12 months

Variable Name:
RHQ031
SAS Label:
Had regular periods in past 12 months
English Text:
{Have you/Has SP} had at least one menstrual period in the past 12 months? (Please do not include bleedings caused by medical conditions, hormone therapy, or surgeries.)
Target:
Females only 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 2567 2567
2 No 2296 4863 RHD043
7 Refused 5 4868 RHQ060
9 Don't know 2 4870 RHQ060
. Missing 444 5314

RHD043 - Reason not having regular periods

Variable Name:
RHD043
SAS Label:
Reason not having regular periods
English Text:
What is the reason that {you have/SP has} not had a period in the past 12 months?
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Pregnancy 17 17
2 Breast feeding 5 22
3 Hysterectomy 779 801
7 Menopause/Change of life 1303 2104
9 Other 163 2267
77 Refused 0 2267
99 Don't know 8 2275
. Missing 3039 5314

RHQ060 - Age at last menstrual period

Variable Name:
RHQ060
SAS Label:
Age at last menstrual period
English Text:
About how old {were you/was SP} when {you/SP} had {your/her} last menstrual period?
English Instructions:
ENTER AGE IN YEARS.
Target:
Females only 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
20 to 59 Range of Values 2143 2143
19 19 years or under 37 2180
60 60 years or older 20 2200
777 Refused 6 2206
999 Don't know 94 2300
. Missing 3014 5314

RHQ070 - Age range at last menstrual period

Variable Name:
RHQ070
SAS Label:
Age range at last menstrual period
English Text:
{Were you/Was SP}...
Target:
Females only 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Younger than 30 4 4
2 30 to 34 4 8
3 35 to 39 4 12
4 40 to 44 13 25
5 45 to 49 21 46
6 50 to 54 15 61
7 55 or older 9 70
77 Refused 0 70
99 Don't know 24 94
. Missing 5220 5314

RHQ074 - Tried for a year to become pregnant?

Variable Name:
RHQ074
SAS Label:
Tried for a year to become pregnant?
English Text:
The next questions are about {your/SP's} pregnancy history. {Have you/Has SP} ever attempted to become pregnant over a period of at least a year without becoming pregnant?
Target:
Females only 18 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 303 303
2 No 2528 2831
7 Refused 3 2834
9 Don't know 2 2836
. Missing 2478 5314

RHQ076 - Seen a DR b/c unable to become pregnant?

Variable Name:
RHQ076
SAS Label:
Seen a DR b/c unable to become pregnant?
English Text:
{Have you/Has SP} ever been to a doctor or other medical provider because {you have/she has} been unable to become pregnant?
Target:
Females only 18 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 207 207
2 No 2626 2833
7 Refused 2 2835
9 Don't know 1 2836
. Missing 2478 5314

RHQ078 - Ever treated for a pelvic infection/PID?

Variable Name:
RHQ078
SAS Label:
Ever treated for a pelvic infection/PID?
English Text:
{Have you/Has SP} ever been treated for an infection in {your/her} fallopian tubes, uterus or ovaries, also called a pelvic infection, pelvic inflammatory disease, or PID?
Target:
Females only 18 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 178 178
2 No 2635 2813
7 Refused 2 2815
9 Don't know 21 2836
. Missing 2478 5314

RHQ131 - Ever been pregnant?

Variable Name:
RHQ131
SAS Label:
Ever been pregnant?
English Text:
The next questions are about {your/SP's} pregnancy history. {Have you/Has SP ever been pregnant? Please include (current pregnancy,) live births, miscarriages, stillbirths, tubal pregnancies and abortions.
English Instructions:
MARK IF KNOWN. OTHERWISE ASK.
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 3412 3412
2 No 640 4052 RHD280
7 Refused 4 4056 RHD280
9 Don't know 1 4057 RHD280
. Missing 1257 5314

RHD143 - Are you pregnant now?

Variable Name:
RHD143
SAS Label:
Are you pregnant now?
English Text:
{Are you/Is SP} pregnant now?
English Instructions:
MARK IF KNOWN. OTHERWISE ASK.
Target:
Females only 20 YEARS - 44 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 67 67
2 No 1009 1076
7 Refused 0 1076
9 Don't know 16 1092
. Missing 4222 5314

RHQ160 - How many times have been pregnant?

Variable Name:
RHQ160
SAS Label:
How many times have been pregnant?
English Text:
How many times {have you/has SP} been pregnant? ({Again, be/Be} sure to count all {your/her} pregnancies including (current pregnancy,) live births, miscarriages, stillbirths, tubal pregnancies or abortions.)
English Instructions:
ENTER NUMBER OF PREGNANCIES.
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 to 10 Range of Values 3379 3379
11 11 or more 30 3409
77 Refused 3 3412
99 Don't know 0 3412
. Missing 1902 5314

RHQ162 - During pregnancy, told you have diabetes

Variable Name:
RHQ162
SAS Label:
During pregnancy, told you have diabetes
English Text:
During {any/your/SP's} pregnancy, {were you/was SP} ever told by a doctor or other health professional that {you/she} had diabetes, sugar diabetes or gestational diabetes? Please do not include diabetes that {you/SP} may have known about before the pregnancy.
English Instructions:
CAPI INSTRUCTION: IF RHQ160 = 1, DISPLAY {your/SP's}. OTHERWISE, DISPLAY {any}.
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 293 293
2 No 3098 3391
3 Borderline 17 3408
7 Refused 1 3409
9 Don't know 1 3410
. Missing 1904 5314

RHD167 - Total number of deliveries

Variable Name:
RHD167
SAS Label:
Total number of deliveries
English Text:
How many deliveries {have you/has SP} had? (Please count all vaginal and Cesarean deliveries and count stillbirths as well as live births.)
English Instructions:
COUNT THE NUMBER OF DELIVERIES, NOT THE NUMBER OF LIVE-BORN CHILDREN. FOR EXAMPLE, IF SP DELIVERED TWINS OR HAD ANY OTHER MULTIPLE BIRTH, COUNT AS A SINGLE DELIVERY. SOFT EDIT: RHD167 MUST BE EQUAL TO OR LESS THAN RHQ160. ERROR MESSAGE: "It is unlikely that the number of deliveries (vaginal and cesarean deliveries combined) is greater than the number of pregnancies. Please verify." SOFT EDIT: IF CURRENTLY PREGNANT (CODED '1' IN RHQ.143) THEN RHD167 SHOULD BE LESS THAN OR EQUAL TO RHQ160 MINUS 1. ERROR MESSAGE: "Since SP is currently pregnant, it is unlikely that the number of vaginal and cesarean deliveries is equal to or greater than the number of pregnancies. Please verify." ENTER NUMBER
Target:
Females only 12 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 4 Range of Values 3067 3067
5 5 or more deliveries 338 3405
77 Refused 2 3407
99 Don't know 1 3408
. Missing 1906 5314

RHQ171 - How many deliveries live birth result?

Variable Name:
RHQ171
SAS Label:
How many deliveries live birth result?
English Text:
How many of {your/her} deliveries resulted {Did {your/her} delivery result} in a live birth?
English Instructions:
CAPI INSTRUCTION: IF SP HAD ONE DELIVERY (SUM OF RHQ166 AND RHQ169 = 1), REPLACE {How many of {your/her} deliveries resulted} WITH {Did {your/her} delivery result}. COUNT THE NUMBER OF TOTAL DELIVERIES, NOT NUMBER OF LIVE-BORN CHILDREN. FOR EXAMPLE, IF SP HAD TWINS OR OTHER MULTIPLE BIRTH, COUNT AS SINGLE DELIVERY. ENTER NUMBER OF DELIVERIES.
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 4 Range of Values 2933 2933
5 5 or more live births 293 3226
77 Refused 2 3228
99 Don't know 0 3228
. Missing 2086 5314

RHQ172 - Any babies weigh 9 lbs or more?

Variable Name:
RHQ172
SAS Label:
Any babies weigh 9 lbs or more?
English Text:
{Did {your/SP's} delivery/Did any of {your/SP's} deliveries} result in a baby that weighed 9 pounds (4082 g) or more at birth? (Please count stillbirths as well as live births.)
English Instructions:
CAPI INSTRUCTION: IF SP HAD ONE DELIVERY (SUM OF RHQ166 AND RHQ169 = 1), DISPLAY {YOUR DELIVERY}. IF SP HAD MORE THAN ONE DELIVERY (SUM OF RHQ166 AND RHQ169 > 1), DISPLAY {ANY OF YOUR DELIVERIES}.
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 581 581
2 No 2630 3211
7 Refused 1 3212
9 Don't know 16 3228
. Missing 2086 5314

RHD180 - Age at first live birth

Variable Name:
RHD180
SAS Label:
Age at first live birth
English Text:
How old {were you/was SP} at the time of {your/her} first live birth?
English Instructions:
ENTER AGE IN YEARS.
Target:
Females only 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
18 to 43 Range of Values 1647 1647
17 17 years or younger 298 1945
45 45 years or older 0 1945
777 Refused 1 1946
999 Don't know 2 1948
. Missing 3366 5314

RHD190 - Age at last live birth

Variable Name:
RHD190
SAS Label:
Age at last live birth
English Text:
How old were you at the time of your last live birth?
English Instructions:
AGE IN YEARS. Derived from RHQ184 - The month and year of {your/her} last delivery, including stillbirths and live births.
Target:
Females only 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
18 to 44 Range of Values 1933 1933
17 17 years or younger 38 1971
45 45 years or older 1 1972
777 Refused 0 1972
999 Don't know 2 1974
. Missing 3340 5314

RHQ197 - How many months ago have baby?

Variable Name:
RHQ197
SAS Label:
How many months ago have baby?
English Text:
How many months ago did {you/SP} have {your/her} baby?
English Instructions:
ENTER NUMBER OF MONTHS
Target:
Females only 20 YEARS - 44 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2 to 24 Range of Values 220 220
1 1 month or less 17 237
777 Refused 0 237
999 Don't know 0 237
. Missing 5077 5314

RHQ200 - Now breastfeeding a child?

Variable Name:
RHQ200
SAS Label:
Now breastfeeding a child?
English Text:
{Are you/Is SP} now breast feeding a child?
Target:
Females only 20 YEARS - 44 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 58 58
2 No 177 235
7 Refused 0 235
9 Don't know 0 235
. Missing 5079 5314

RHD280 - Had a hysterectomy?

Variable Name:
RHD280
SAS Label:
Had a hysterectomy?
English Text:
{Have you/Has SP} had a hysterectomy that is, surgery to remove {your/her} uterus or womb?
English Instructions:
MARK IF KNOWN. OTHERWISE ASK.
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 901 901
2 No 3129 4030 RHQ305
7 Refused 0 4030 RHQ305
9 Don't know 7 4037 RHQ305
. Missing 1277 5314

RHQ305 - Had both ovaries removed?

Variable Name:
RHQ305
SAS Label:
Had both ovaries removed?
English Text:
{Have you/Has SP} had both of {your/her} ovaries removed (either when {you/she} had {your/her} uterus removed or at another time)?
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 471 471
2 No 3514 3985 RHQ540
7 Refused 0 3985 RHQ540
9 Don't know 51 4036 RHQ540
. Missing 1278 5314

RHQ332 - Age when both ovaries removed

Variable Name:
RHQ332
SAS Label:
Age when both ovaries removed
English Text:
How old {were you/was SP} when {you/she} had {your/her} ovaries removed or last ovary removed if removed at different times?
English Instructions:
ENTER AGE IN YEARS
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
22 to 59 Range of Values 426 426
19 19 years or under 2 428
60 60 years or older 36 464
777 Refused 0 464
999 Don't know 7 471
. Missing 4843 5314

RHQ540 - Ever use female hormones?

Variable Name:
RHQ540
SAS Label:
Ever use female hormones?
English Text:
{Have you/Has SP} ever used female hormones such as estrogen and progesterone? Please include any forms of female hormones, such as pills, cream, patch, and injectables, but do not include birth control methods or use for infertility.
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 675 675
2 No 3356 4031 End of Section
7 Refused 5 4036 End of Section
9 Don't know 18 4054 End of Section
. Missing 1260 5314

RHQ542A - Hormone pills used

Variable Name:
RHQ542A
SAS Label:
Hormone pills used
English Text:
Which forms of female hormones {have you/has SP} used.
English Instructions:
CODE ALL THAT APPLY.
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
10 Pills 512 512
77 Refused 0 512
99 Don't know 5 517
. Missing 4797 5314

RHQ542B - Hormone patches used

Variable Name:
RHQ542B
SAS Label:
Hormone patches used
English Text:
Which forms of female hormones {have you/has SP} used.
English Instructions:
CODE ALL THAT APPLY.
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
11 Patches 87 87
. Missing 5227 5314

RHQ542C - Hormone cream/suppository/injection used

Variable Name:
RHQ542C
SAS Label:
Hormone cream/suppository/injection used
English Text:
Which forms of female hormones {have you/has SP} used.
English Instructions:
CODE ALL THAT APPLY.
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
12 Cream/suppository/injection 171 171
. Missing 5143 5314

RHQ542D - Other form of female hormone used

Variable Name:
RHQ542D
SAS Label:
Other form of female hormone used
English Text:
Which forms of female hormones {have you/has SP} used.
English Instructions:
CODE ALL THAT APPLY.
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
13 Other 11 11
. Missing 5303 5314

RHQ554 - Use hormone pills w/estrogen only

Variable Name:
RHQ554
SAS Label:
Use hormone pills w/estrogen only
English Text:
{Have you/Has SP} ever taken female hormone pills containing estrogen only (like Premarin)? (Do not include birth control pills.)
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 359 359
2 No 112 471 RHQ570
7 Refused 0 471 RHQ570
9 Don't know 41 512 RHQ570
. Missing 4802 5314

RHQ570 - Used estrogen/progestin combo pills

Variable Name:
RHQ570
SAS Label:
Used estrogen/progestin combo pills
English Text:
{Have you/Has SP} taken female hormone pills containing both estrogen and progestin (like Prempro, Premphase)? (Do not include birth control pills.)
Target:
Females only 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 84 84
2 No 379 463
7 Refused 0 463
9 Don't know 49 512
. Missing 4802 5314