import { type BmiCategory } from '../bmi-calculator/bmi';
import type { Plurality } from '../_shared/obstetrics';
export interface GainBand {
    /** Lower bound, kg. */
    min: number;
    /** Upper bound, kg. */
    max: number;
}
export type GainStatus = 'below' | 'within' | 'above';
/** IOM (2009) total recommended gain for a singleton pregnancy, kg. */
export declare const TOTAL_GAIN_BANDS: Record<BmiCategory, GainBand>;
/**
 * IOM (2009) total recommended gain for a TWIN pregnancy, kg. The IOM gives
 * no firm range for underweight twins (insufficient evidence), so that
 * category is intentionally absent and resolves to `null`. There is no IOM
 * range for triplets at all.
 */
export declare const TWIN_TOTAL_GAIN_BANDS: Partial<Record<BmiCategory, GainBand>>;
/** Resolve the total-gain band for a category + plurality, or `null` if the IOM gives none. */
export declare function totalGainBand(category: BmiCategory, plurality?: Plurality): GainBand | null;
/** IOM (2009) mean rate of gain in the 2nd/3rd trimester, kg per week. */
export declare const RATE_BANDS: Record<BmiCategory, GainBand>;
/** First-trimester total gain band, kg (category-independent in IOM). */
export declare const FIRST_TRIMESTER_GAIN: GainBand;
/** Completed weeks counted as the first trimester for gain purposes. */
export declare const FIRST_TRIMESTER_WEEKS = 13;
export interface WeightGainInput {
    /** Pre-pregnancy BMI (kg/m²) — drives the category. */
    prePregnancyBmi: number;
    /** Pre-pregnancy weight, kg. */
    prePregnancyWeightKg: number;
    /** Current weight, kg. */
    currentWeightKg: number;
    /** Completed gestational weeks. */
    gestationalWeeks: number;
    /** Number of babies. Defaults to `'singleton'`. */
    plurality?: Plurality;
}
export interface WeightGainResult {
    category: BmiCategory;
    /** Number of babies the assessment was computed for. */
    plurality: Plurality;
    /**
     * Recommended TOTAL gain across the whole pregnancy, or `null` when the IOM
     * publishes no range (triplets, and underweight twins).
     */
    totalRange: GainBand | null;
    /** Recommended gain accumulated by the current week, or `null` (see above). */
    recommendedToDate: GainBand | null;
    /** Actual gain so far (current − pre-pregnancy), kg. */
    actualGainKg: number;
    /** Where the actual gain sits against the to-date recommendation, or `null`. */
    status: GainStatus | null;
    /**
     * Estimated 2nd/3rd-trimester average weekly gain to date (kg/week), or `null`
     * before week 14 / when no singleton rate band applies. A snapshot estimate
     * (assumes the mid first-trimester gain), not a between-visit measurement.
     */
    weeklyRate: number | null;
    /** Where the weekly rate sits against the IOM rate band, or `null`. */
    rateStatus: GainStatus | null;
}
export declare function recommendedGainToDate(category: BmiCategory, weeks: number, plurality?: 'singleton'): GainBand;
export declare function recommendedGainToDate(category: BmiCategory, weeks: number, plurality: Plurality): GainBand | null;
export declare function assessWeightGain(input: WeightGainInput): WeightGainResult;
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